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MEMORANDUM

PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT

TO: Vivienne St. Claire, Responsible Partner, Capital Markets Robert Adeyemi, Billing Partner, Capital Markets

FROM: Claire Dempsey, Lead Associate, Capital Markets

CC: Audrey Zhou, Working Associate, Capital Markets Leonard Cross, Specialist Partner, Tax

DATE: January 30, 2026

RE: Framework for Calderwood & Harkness LLP Negative Assurance Letter and 10b-5 Disclosure Letter — Halcyon Semiconductor AG Level III ADR Initial Public Offering

MATTER NO.: 1032-00003

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I. Purpose and Executive Summary

This memorandum establishes the internal framework, scope, methodology, and factual predicate for Calderwood & Harkness LLP's ("C&H" or the "Firm") delivery of a negative assurance letter (commonly referred to as a "10b-5 letter" or "10b-5 disclosure letter") to the underwriting syndicate in connection with the initial public offering (the "Offering") of American Depositary Shares ("ADSs") of Halcyon Semiconductor Aktiengesellschaft ("Halcyon" or the "Company"). Specifically, the Firm will deliver:

(a) a negative assurance letter addressed to the underwriting syndicate — consisting of Westbridge Securities LLC (lead left bookrunner), Pinnacle Morgan & Co., Inc. (joint bookrunner), Andover Barcliffe Group Inc. (joint bookrunner), and Northpointe Capital LLC (co-manager) (collectively, the "Underwriters"); and

(b) such letter to be delivered at the closing of the Offering (target closing and settlement date: July 6, 2026, T+2 from pricing target of July 1, 2026) as a condition to the Underwriters' obligations under the underwriting agreement.

The negative assurance letter will be delivered pursuant to the conditions to closing set forth in the underwriting agreement (the "Underwriting Agreement"), which will be governed by the laws of the State of New York, among Halcyon Semiconductor Aktiengesellschaft, the selling shareholders — Rheintal Industrieholding GmbH ("Rheintal") and Kestrel Capital Partners AG ("Kestrel") (together, the "Selling Shareholders") — and the several Underwriters, with Westbridge Securities LLC acting as representative of the several Underwriters (in such capacity, the "Representative").

The negative assurance letter is a customary closing deliverable in registered public offerings under the Securities Act of 1933, as amended (the "Securities Act"), and serves as a key element of the Underwriters' due diligence defense under Sections 11 and 12(a)(2) of the Securities Act. The letter provides comfort to the Underwriters that, based on the Firm's professional participation in the preparation of the registration statement and the prospectus, and subject to stated qualifications and limitations, nothing has come to the Firm's attention that causes it to believe that the offering documents contain a material misstatement or omission. While the letter does not constitute a guarantee of accuracy nor serve as a substitute for the Underwriters' own independent due diligence, it is an essential component of the closing mechanics and is invariably required by underwriting syndicates in transactions of this nature and magnitude.

The Registration Statement will be filed on Form F-1 under the Securities Act (the "Registration Statement"), registering ADSs, each representing two (2) ordinary shares (Stammaktien) of Halcyon, par value €1.00 per share, for listing on the Nasdaq Global Select Market under the ticker symbol "HCYN." The Company qualifies as a foreign private issuer ("FPI") under Rule 3b-4 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and the Registration Statement will avail itself of certain accommodations available to FPIs under the Securities Act and Exchange Act, including financial statements prepared in accordance with International Financial Reporting Standards ("IFRS") as issued by the International Accounting Standards Board without reconciliation to U.S. GAAP.

The Offering is structured to include targeted gross proceeds of approximately $900,000,000 through the offering of 21,400,000 ADSs in the base deal — consisting of 15,000,000 ADSs issued by the Company in the primary offering (representing 30,000,000 newly issued ordinary shares) and 6,400,000 ADSs offered by the Selling Shareholders in the secondary offering (representing 12,800,000 existing ordinary shares) — together with an overallotment option granted to the Underwriters for up to 3,210,000 additional ADSs (representing 6,420,000 additional ordinary shares), exercisable for up to 30 days following pricing.

It should be noted that Varen & Kessler LLP ("V&K"), acting through Martin Ashford, Partner, and Priya Ranganathan, Senior Associate, serves as United States counsel to the Underwriters. V&K will independently evaluate the scope and sufficiency of C&H's negative assurance letter. C&H should expect that V&K will negotiate the language, qualifications, and conditions of the letter, as is customary in transactions of this type. The Firm's engagement team should anticipate and prepare for negotiation sessions with V&K regarding the scope of the letter, the adequacy of the factual predicate, and any additional conditions or carve-outs that V&K may request on behalf of the Underwriters.

This memorandum is organized to address: (i) the legal standard and basis for the negative assurance letter; (ii) the scope of the letter and sections covered and excluded; (iii) the due diligence activities forming the factual predicate; (iv) the form and content of the letter; (v) coordination with other closing deliverables; (vi) documentation and record-keeping requirements; (vii) risk considerations and limitations; and (viii) team responsibilities and next steps.

II. Legal Standard and Basis for the Negative Assurance Letter

A. Nature of the 10b-5 Letter

The negative assurance letter, colloquially referred to as a "10b-5 letter," is a statement by issuer's counsel that, based on counsel's participation in the preparation of the Registration Statement on Form F-1 and the prospectus included therein (the "Prospectus"), and subject to stated qualifications and limitations, nothing has come to the attention of the Firm that causes it to believe that:

(i) the Registration Statement, as of the date of its effectiveness, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading; or

(ii) the Prospectus, as of its date and as of the closing date, contained or contains any untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

It is critical that the engagement team understand the precise nature of this undertaking and its inherent limitations. The negative assurance letter is fundamentally different from an affirmative legal opinion on compliance with the Securities Act or any other body of law. It is not a guarantee of accuracy, completeness, or legal compliance. Nor does it constitute an independent investigation or audit of the facts and circumstances underlying the disclosure contained in the Registration Statement and the Prospectus. Rather, the letter is a report by counsel on the results of counsel's professional involvement in the preparation of the offering documents — a statement that, in the course of performing its customary role as securities counsel, no information came to the Firm's attention that would cause it to believe that the disclosure was materially deficient.

The distinction between the negative assurance letter and the role of auditors is particularly important. Counsel is not conducting an audit or review of financial information; counsel does not possess the professional qualifications to do so. The letter expressly disclaims reliance on financial data, which is the domain of the Company's independent registered public accounting firm, Blackmere & Whitfield LLP and its affiliated German Wirtschaftsprüfungsgesellschaft. Similarly, counsel does not independently verify the accuracy of every factual assertion in the Prospectus, though counsel does conduct verification procedures for material factual claims as part of its due diligence program.

The letter's value lies in the disciplinary function it serves: by requiring counsel to deliver the letter as a closing condition, the offering process creates powerful incentives for counsel to conduct thorough due diligence and to insist on complete and accurate disclosure throughout the drafting process. The letter thus serves as both a professional undertaking and a quality assurance mechanism for the benefit of the Underwriters and, ultimately, investors.

B. Statutory Framework

The negative assurance letter derives its significance from the federal securities law liability framework applicable to registered public offerings. The principal statutory provisions are summarized below.

Section 11 of the Securities Act. Section 11 imposes strict liability on the issuer for material misstatements or omissions in the registration statement at the time of its effectiveness. Unlike the issuer, underwriters are not subject to strict liability under Section 11 but instead may assert a "due diligence" defense under Section 11(b)(3)(A). To establish this defense, an underwriter must demonstrate that, after reasonable investigation, it had reasonable ground to believe, and did believe, that the statements in the registration statement were true and that there was no omission to state a material fact required to be stated therein or necessary to make the statements therein not misleading. The standard of reasonableness is that required of a prudent person in the management of his own property. The negative assurance letter serves as one evidentiary component of the underwriters' reasonable investigation, though it is not sufficient standing alone to establish the defense.

Section 12(a)(2) of the Securities Act. Section 12(a)(2) provides a right of rescission or damages to purchasers who acquire securities by means of a prospectus or oral communication that contains an untrue statement of a material fact or omits to state a material fact necessary in order to make the statements, in the light of the circumstances under which they were made, not misleading. A due diligence defense is available to sellers (including underwriters) who can demonstrate that they did not know, and in the exercise of reasonable care could not have known, of the misstatement or omission. The negative assurance letter supports this defense in a manner analogous to its role under Section 11.

Rule 10b-5 under the Exchange Act. Rule 10b-5 is the general anti-fraud provision promulgated under Section 10(b) of the Exchange Act, which prohibits fraudulent or deceptive conduct in connection with the purchase or sale of securities, including the making of any untrue statement of a material fact or any omission of a material fact necessary in order to make the statements made, in the light of the circumstances under which they were made, not misleading. Although the letter is colloquially called a "10b-5 letter," it is important to recognize that the letter does not constitute an opinion on Rule 10b-5 liability per se. Rule 10b-5 liability requires a showing of scienter (intentional or reckless conduct), which is a distinct element not addressed by the negative assurance letter. Rather, the letter addresses the disclosure standards — materiality, truthfulness, and completeness of statements — that parallel Rule 10b-5's substantive requirements.

ABA TriBar Opinion Committee and Market Practice. The form and content of negative assurance letters have developed over decades of market practice and have been the subject of extensive commentary by the American Bar Association's TriBar Opinion Committee and its successor committees. The TriBar Committee's 2004 report and subsequent updates provide guidance on the scope of the factual predicate necessary to support a negative assurance letter, the appropriate qualifications and limitations, and the relationship between the letter and the broader due diligence program. For cross-border ADR IPOs by foreign private issuers, market practice recognizes the need for coordination with local counsel and appropriate reliance on foreign counsel opinions for matters outside the scope of U.S. securities counsel's expertise. C&H's letter will be prepared in accordance with these principles and with prevailing market practice for Level III ADR IPOs.

C. Significance for Underwriters' Due Diligence Defense

The Underwriters — Westbridge, Pinnacle Morgan, Andover Barcliffe, and Northpointe — rely on the negative assurance letter as one component of their "reasonable investigation" defense under Section 11(b)(3). The Supreme Court's decision in Escott v. BarChris Construction Corp., 283 F. Supp. 643 (S.D.N.Y. 1968), and its progeny establish that the scope of reasonable investigation required of underwriters is greater than that required of outside directors or other non-expert participants, reflecting the underwriters' gatekeeper role in the capital markets. Accordingly, the Underwriters' due diligence program must be comprehensive and well-documented.

The negative assurance letter alone does not establish the due diligence defense. It must be supported by the totality of the Underwriters' due diligence program, including, without limitation:

• Management interviews conducted by the Underwriters and their counsel (V&K);

• Comfort letters from Blackmere & Whitfield LLP/GmbH WPG covering financial statements and specified financial data;

• Legal opinions from German issuer counsel (Bähr Stein Rechtsanwälte) and German underwriters' counsel (Prumvane Thornton LLP);

• Review of corporate records, material contracts, and regulatory filings;

• Independent research on industry conditions and competitive dynamics;

• Officer and director certificates; and

• Any additional diligence activities undertaken by the Underwriters or V&K.

It should further be noted that V&K, as counsel to the Underwriters, will also deliver its own negative assurance letter. The two letters — C&H's as issuer's counsel and V&K's as underwriters' counsel — are complementary and together provide the documentary foundation for the Underwriters' disclosure-related due diligence. V&K's letter will be based on V&K's own independent participation in the preparation and review of the Registration Statement and Prospectus, and V&K will conduct its own due diligence activities to support its letter. The existence of V&K's letter does not diminish the importance or scope of C&H's letter; rather, the two letters reflect different vantage points and different professional involvement in the offering process.

III. Scope of the Negative Assurance Letter

A. Documents Covered

The negative assurance letter is expected to cover the following documents:

Registration Statement on Form F-1. The letter will cover the Registration Statement on Form F-1 filed with the Securities and Exchange Commission (the "SEC"), including all amendments thereto (Amendment No. 1 target: May 26, 2026), through the date of declaration of effectiveness by the SEC (target: June 22, 2026). This includes all exhibits to the Registration Statement to the extent they constitute part of the registration statement for purposes of Section 11.

Prospectus. The letter will cover the Prospectus included in the Registration Statement, including any prospectus supplements, the preliminary prospectus (the "Red Herring"), and any final prospectus filed pursuant to Rule 424(b) under the Securities Act. The negative assurance statement with respect to the Prospectus will address the Prospectus both as of its date and as of the closing date (July 6, 2026).

Registration Statement on Form F-6. The Registration Statement on Form F-6, which registers the ADSs evidenced by American Depositary Receipts ("ADRs") issued by Meridian Trust Company, N.A. as depositary (the "Depositary"), presents a threshold scope question. Form F-6 is a registration statement for the ADSs themselves and typically contains limited disclosure, primarily the deposit agreement and related forms. It is the Firm's recommendation that the scope of the negative assurance letter be limited to the Registration Statement on Form F-1 and the Prospectus included therein, with the Form F-6 addressed only insofar as it incorporates by reference or is part of the F-1 filing package. This recommendation is based on the fact that the Form F-6 is essentially a mechanical registration of the ADSs and does not contain the type of substantive disclosure that is the subject of the negative assurance letter. This scope limitation should be confirmed with Vivienne St. Claire and negotiated with V&K.

Free Writing Prospectuses and Issuer Free Writing Prospectuses. To the extent that C&H is involved in the preparation of any free writing prospectus or issuer free writing prospectus used in connection with the Offering, as defined in Rule 164 and Rule 433 under the Securities Act, the letter may extend to such materials. The scope of coverage for any free writing prospectus should be determined on a case-by-case basis depending on the nature and extent of C&H's involvement in its preparation.

Road Show Materials. If C&H is involved in the preparation of road show materials — including any electronic road show presentation — the letter may need to address such materials. The extent of coverage will depend on the nature of C&H's participation and whether the materials constitute free writing prospectuses subject to filing requirements. This issue should be discussed at the organizational meeting and with V&K.

B. Sections/Portions Expressly Excluded from Negative Assurance

The negative assurance letter will expressly exclude the following portions of the Registration Statement and the Prospectus from its coverage:

Financial Statements and Related Notes. The audited consolidated financial statements of the Company for the fiscal years ended December 31, 2023, December 31, 2024, and December 31, 2025, and the notes thereto, as audited or reviewed by Blackmere & Whitfield, are excluded. These financial statements are covered by the auditors' reports and by the comfort letters delivered pursuant to SAS No. 72 (Letters for Underwriters and Certain Other Requesting Parties) and ISAE 3000 (International Standard on Assurance Engagements). C&H lacks the professional qualifications to address the accuracy of financial statements and accounting disclosures.

Financial Schedules and Statistical Data. Financial schedules and statistical data derived from the Company's accounting records are excluded to the extent such data falls within the scope of the auditors' comfort letters. This includes, without limitation, tables of selected financial data, ratio calculations, and financial data presented in the text of the Prospectus that has been "circled" or "tick-marked" for comfort letter coverage.

Forward-Looking Statements and Projections. Forward-looking statements and projections that are identified as such and that fall within the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 ("PSLRA") and the Securities Act are excluded from the scope of the negative assurance letter. The Prospectus will contain extensive forward-looking statements regarding the Company's strategic plans, anticipated capital expenditures (including Fab 3 expansion), projected market opportunities, and expected financial performance, all of which will be accompanied by appropriate cautionary language identifying important factors that could cause actual results to differ materially.

Expert Portions. Any portions of the Registration Statement or the Prospectus made on the authority of, or constituting the report of, an expert — including the auditors' reports of Blackmere & Whitfield and any geological, engineering, or other technical reports — are excluded. Based on current information, no geological or engineering reports are expected to be included in the Registration Statement for this Offering, but this exclusion is included as a standard protective measure.

Statements of Regulatory Bodies. Statements made on the authority of the SEC, the Nasdaq Stock Market LLC, the German Federal Financial Supervisory Authority (Bundesanstalt für Finanzdienstleistungsaufsicht or "BaFin"), or other regulatory bodies are excluded from the scope of negative assurance.

German Tax Disclosure. German tax disclosure in the Prospectus, to the extent prepared by or attributable to Bähr Stein Rechtsanwälte in its capacity as German tax counsel to the Company, is excluded. The German statutory withholding tax rate of 26.375% (including solidarity surcharge) and the applicable treaty rate of 15% for qualified U.S. holders are matters of German tax law outside the scope of C&H's professional competence.

German Corporate Law Matters. All matters of German corporate law, including the validity of the ordinary shares under German law, the authority of the Company's management board (Vorstand) and supervisory board (Aufsichtsrat) to approve the Offering, and compliance with German securities regulations, are within the province of Bähr Stein Rechtsanwälte as German issuer counsel and are excluded from C&H's negative assurance letter.

C. Sections Requiring Special Attention

The following sections of the Prospectus present areas of heightened complexity, materiality, or risk and will require the engagement team's focused attention during the due diligence and drafting process:

Risk Factors. The Prospectus will contain a comprehensive risk factor section addressing, among other things: semiconductor industry cyclicality and competitive dynamics; risks related to the Company's silicon carbide (SiC) and gallium nitride (GaN) technology platforms; operational risks associated with the Company's manufacturing facilities in Munich, Dresden (Fab 2 and Fab 3 under construction), and Brno; risks related to the Company's operations in the People's Republic of China through Halcyon Shanghai Semiconductor Co., Ltd.; risks associated with dual listing on Nasdaq and the Frankfurt Stock Exchange; the Company's status as a foreign private issuer; passive foreign investment company ("PFIC") risk; foreign currency fluctuations between the euro, U.S. dollar, Chinese renminbi, and Czech koruna; and risks related to export controls (Export Administration Regulations / International Traffic in Arms Regulations) and international sanctions regimes. The risk factor section is among the most closely scrutinized portions of the Prospectus for purposes of both SEC review and the due diligence defense, and the engagement team must ensure that identified risks are disclosed with sufficient specificity and candor.

Business Description. The business description must accurately present Halcyon's operations, including its workforce of approximately 8,400 employees, its revenue of €3.82 billion for fiscal year 2025 (unaudited), its EBITDA of €1.069 billion (28.0% margin), and its competitive positioning in the global power semiconductor market. Claims regarding market position, technology leadership, and competitive advantages must be verified against independent source materials where available.

Use of Proceeds. The Prospectus will disclose the Company's intended use of the net proceeds from the Offering, currently estimated as follows: approximately $280 million for the expansion of Fab 3 in Dresden; approximately $140 million for GaN research and development programs; approximately $100 million for repayment of amounts outstanding under the Company's revolving credit facility; and the balance of approximately $87.95 million for general corporate purposes. Each use of proceeds allocation must be consistent with management's representations and Board approvals and must be presented with appropriate flexibility language where final allocations are subject to management's discretion.

Capitalization and Dilution. The Prospectus will present the Company's capitalization and dilution on both a pre-offering and post-offering basis. The Company currently has 215,000,000 ordinary shares outstanding; following the issuance of 30,000,000 new ordinary shares in the primary offering, the Company will have approximately 245,000,000 ordinary shares outstanding (prior to any exercise of the overallotment option). The ADS-to-ordinary share ratio is 1:2 (each ADS represents two ordinary shares). Dilution calculations must be reviewed for mathematical accuracy and consistency with the financial statements.

Related-Party Transactions. The Prospectus must disclose the Company's transactions with related parties, including Rheintal Industrieholding GmbH, which is controlled by the Wendt family. Margarethe Wendt, the principal of Rheintal, is the sister of the Company's Chief Executive Officer, Dr. Friedrich Wendt. Rheintal holds 22.3% of the Company's pre-IPO ordinary shares and is selling shares representing 4,250,000 ADSs (8,500,000 ordinary shares) in the secondary offering. Following the Offering, Rheintal's ownership will be reduced to approximately 16.1% of the outstanding ordinary shares (assuming no exercise of the overallotment option). Any ongoing commercial arrangements, management agreements, or other transactions between the Company and Rheintal must be fully disclosed and reviewed for compliance with Item 7.B of Form 20-F.

Selling Shareholder Disclosure. In addition to Rheintal, Kestrel Capital Partners AG — a private equity firm managed by Henrik Sørensen — is selling shares representing 2,150,000 ADSs (4,300,000 ordinary shares). Kestrel holds 9.7% of the Company's pre-IPO ordinary shares, and its ownership will be reduced to approximately 6.8% post-Offering. The disclosure regarding the Selling Shareholders' ownership, selling motivations, and any agreements or arrangements with the Company must be verified.

Description of ADSs and Deposit Agreement Terms. The Prospectus will include a description of the ADSs, the terms of the deposit agreement with Meridian Trust Company, N.A., and the rights of ADS holders. This section must accurately reflect the deposit agreement and distinguish the rights of ADS holders from the rights of ordinary shareholders under German law.

Management and Supervisory Board. The Prospectus will disclose the composition of the Company's Vorstand and Aufsichtsrat, including: Dr. Friedrich Wendt, Chief Executive Officer (Vorstandsvorsitzender); Katarina Dalmqvist, Chief Financial Officer; Dr. Marcus Helder, Chief Technology Officer; Ingrid Baumann, Chief Operating Officer; Wilhelm Ostermann, General Counsel and Company Secretary; and Prof. Dr. Anneliese Voss, Chair of the Supervisory Board. Biographical information, compensation data, and any relationships or transactions requiring disclosure must be verified through director and officer questionnaires.

Lock-Up Disclosure. The Prospectus will describe the 180-day lock-up period from the pricing date (July 1, 2026) applicable to the Company, the Selling Shareholders, and the Company's officers and directors, with Westbridge Securities LLC serving as the lock-up consent agent. The lock-up terms must be accurately described and consistent with the lock-up agreements to be executed by the relevant parties.

Taxation Section. The U.S. federal income tax consequences section of the Prospectus will be prepared by Leonard Cross. This section will address, among other things, the taxation of dividends and capital gains to U.S. holders of ADSs, the German statutory withholding tax rate of 26.375% (including solidarity surcharge) and the reduced treaty rate of 15% for qualified U.S. holders under the U.S.-Germany income tax treaty, and the PFIC analysis. Based on preliminary review, Leonard Cross has reached the preliminary conclusion that the Company is not a PFIC, as it satisfies the active business exception. The PFIC analysis is of particular importance given the Company's substantial cash position and the potential for passive income generated by investment holdings. This analysis must be finalized and documented in a separate PFIC memorandum prior to first draft circulation.

IV. Factual Predicate — Due Diligence Process

A. Due Diligence Activities Forming the Basis for Negative Assurance

The integrity and credibility of C&H's negative assurance letter depend entirely on the thoroughness and quality of the due diligence process that underlies it. The Firm cannot deliver the letter in good faith unless it has conducted a comprehensive due diligence program sufficient to establish the factual predicate for the negative assurance statement. The following categories of due diligence activity must be completed prior to delivery of the letter:

1. Document Review. C&H will conduct a comprehensive review of the Company's corporate organizational documents, material contracts, intellectual property portfolio documentation, litigation files, regulatory filings, insurance policies, employee benefit plan documents (including the Employee Share Ownership Trust, which holds approximately 3.1% of the Company's ordinary shares, or 6,665,000 shares), environmental permits, and related-party transaction documentation. The scope of document review is defined by the comprehensive due diligence request list circulated to Halcyon and Bähr Stein Rechtsanwälte, which covers the following categories in detail:

• Corporate organizational documents, including the Company's articles of association (Satzung), Commercial Register extracts from the Handelsregister maintained at the Amtsgericht München (registration number HRB 217458), minutes of meetings of the Vorstand, Aufsichtsrat, and Hauptversammlung (general shareholders' meeting), and shareholder agreements;

• All material contracts to which the Company or any of its subsidiaries is a party, including customer contracts, supply agreements, licensing agreements, joint venture agreements, real property leases, credit facilities, and any contracts that would be required to be filed as exhibits to the Registration Statement under Item 601 of Regulation S-K (as applied to FPIs);

• intellectual property portfolio documentation, including patents, patent applications, trademarks, trade secrets, and any material licensing or cross-licensing arrangements;

• Litigation files, including all pending, threatened, or recently concluded litigation, arbitration, or regulatory proceedings involving the Company or any of its subsidiaries;

• Regulatory filings with German, EU, U.S., Chinese, Singaporean, and Czech regulatory authorities;

• Insurance policies covering the Company's assets, operations, and officers and directors;

• Employee benefit plan documents and employment agreements for key personnel; and

• Related-party transaction documentation, including all agreements between the Company and Rheintal Industrieholding GmbH, Kestrel Capital Partners AG, or entities controlled by or affiliated with members of the Vorstand or Aufsichtsrat.

2. Management Interviews. C&H will conduct in-person or video conference interviews with the following members of Halcyon's senior management team. These interviews are critical to establishing the factual predicate and ensuring that the engagement team has a thorough understanding of the Company's business, operations, and risk profile:

• Dr. Friedrich Wendt, Chief Executive Officer — corporate strategy, business overview, competitive landscape, market positioning in the global power semiconductor industry, key customer and supplier relationships, and related-party transactions with Rheintal Industrieholding GmbH;

• Katarina Dalmqvist, Chief Financial Officer — financial matters, capital structure and debt obligations, internal controls over financial reporting, disclosure controls and procedures, intended use of proceeds from the Offering, and accounting policies;

• Dr. Marcus Helder, Chief Technology Officer — technology platform and product roadmap, intellectual property portfolio, research and development programs (including GaN and SiC programs), and competitive technology landscape;

• Ingrid Baumann, Chief Operating Officer — manufacturing operations at the Munich headquarters, Dresden (Fab 2 operational and Fab 3 under construction), and Brno facilities, supply chain management, capacity utilization, and construction timeline for Fab 3;

• Wilhelm Ostermann, General Counsel and Company Secretary — pending and threatened litigation, regulatory proceedings, compliance programs (anti-corruption, export controls, sanctions), related-party transactions, and corporate governance structure;

• Additional interviews with divisional management and subsidiary heads — as warranted by the initial due diligence review, including the head of Halcyon Semiconductor USA Inc. in Santa Clara (to cover U.S. operations, customers, and regulatory compliance) and management of Halcyon Shanghai Semiconductor Co., Ltd. (to cover PRC operations, regulatory environment, and data privacy compliance).

Each management interview will be documented in a written interview summary prepared by the attending associates and reviewed by the supervising partner. Interview summaries will include a record of attendees, the date, time, and format of the interview, the topics covered, and any follow-up items identified.

3. Legal and Regulatory Review. C&H will conduct a thorough analysis of the Company's legal and regulatory environment, with particular emphasis on:

• Pending, threatened, or recently concluded litigation, arbitration, or regulatory proceedings;

• Compliance with the sanctions programs administered by the Office of Foreign Assets Control ("OFAC") of the U.S. Department of the Treasury, EU sanctions regulations, and comparable programs administered by other jurisdictions in which the Company operates;

• Compliance with the Foreign Corrupt Practices Act ("FCPA"), the UK Bribery Act 2010, and applicable local anti-corruption laws;

• Compliance with U.S. export control regulations, including the Export Administration Regulations ("EAR") and the International Traffic in Arms Regulations ("ITAR"), which are of critical importance for semiconductor manufacturers — particularly with respect to exports of controlled semiconductor technology and equipment, and especially concerning the Company's operations in China through Halcyon Shanghai Semiconductor Co., Ltd.; and

• Environmental, health, and safety regulatory compliance at the Company's manufacturing facilities.

The export control and sanctions compliance analysis is of heightened importance in this transaction given the current regulatory environment governing semiconductor exports to the PRC and the Company's WFOE structure in Shanghai. C&H will review the Company's export control compliance programs, export license applications and determinations, classification of products under the Commerce Control List, and any instances of potential violations or voluntary self-disclosures.

4. Subsidiary Review. C&H will conduct due diligence on each of the Company's material subsidiaries to confirm the accuracy of the subsidiary disclosure in the Registration Statement and to identify any subsidiary-level risks, liabilities, or regulatory issues that may be material to the Company on a consolidated basis. The material subsidiaries include:

• Halcyon Semiconductor USA Inc. — organized under the laws of the State of Delaware; Employer Identification Number 84-3927561; principal office located in Santa Clara, California; engages in sales, marketing, and applications engineering for the North American market;

• Halcyon Power Solutions GmbH — organized under the laws of Germany; located in Dresden; operates the Company's Fab 2 wafer fabrication facility and oversees construction of Fab 3;

• Halcyon Asia Pacific Pte. Ltd. — organized under the laws of Singapore; serves as the Company's regional headquarters for the Asia-Pacific region (excluding the PRC);

• Halcyon Shanghai Semiconductor Co., Ltd. — organized as a wholly foreign-owned enterprise (WFOE) under the laws of the People's Republic of China; located in Shanghai; engages in semiconductor design, testing, and customer support activities for the Chinese market; and

• Halcyon Automotive Components s.r.o. — organized under the laws of the Czech Republic; located in Brno; engages in manufacturing of automotive-grade power semiconductor modules.

5. Third-Party Reports and Certificates. C&H will review the following third-party reports and certificates that form part of the closing deliverable package and contribute to the factual predicate for the negative assurance letter:

• Comfort letters from Blackmere & Whitfield LLP (Graham Templeton, Engagement Partner, New York) and Blackmere & Whitfield GmbH Wirtschaftsprüfungsgesellschaft (Dieter Kaufmann, Lead Partner, Munich), delivered pursuant to SAS No. 72 and ISAE 3000;

• Legal opinions from Bähr Stein Rechtsanwälte (German issuer counsel) and Prumvane Thornton LLP (German underwriters' counsel; Dr. Stefan Braun, Partner);

• Officer certificates executed by Dr. Friedrich Wendt (CEO) and Katarina Dalmqvist (CFO), certifying as to the accuracy of statements in the Registration Statement and the absence of material adverse changes;

• General Counsel / Secretary certificate from Wilhelm Ostermann, confirming Vorstand and Aufsichtsrat resolutions, organizational documents, and other corporate matters;

• Selling shareholder certificates from Rheintal Industrieholding GmbH (executed by Margarethe Wendt) and Kestrel Capital Partners AG (executed by Henrik Sørensen), confirming the accuracy of the Selling Shareholder information in the Prospectus.

6. Prospectus Drafting Participation. C&H's active participation in all drafting sessions is an essential component of the factual predicate. Through the drafting process, counsel develops a detailed understanding of the disclosure and has the opportunity to identify and address potential misstatements or omissions in real time. The engagement team will participate in all drafting sessions, including the all-parties drafting session scheduled for March 23–24, 2026. C&H will be responsible for the review and revision of all non-financial portions of the Prospectus and will coordinate with Bähr Stein Rechtsanwälte regarding German law disclosure contained in the Prospectus.

7. SEC Comment Letter Responses. C&H will participate in formulating responses to SEC Division of Corporation Finance staff comments on the Registration Statement. Based on typical review timelines for FPI IPOs, the Firm estimates that the first SEC comment letter may be received on or around May 12, 2026, following the confidential submission of the draft Registration Statement on April 14, 2026. Amendment No. 1, incorporating responses to the first round of comments, is targeted for filing on or about May 26, 2026. The comment letter process is an important element of the factual predicate because it requires counsel to analyze and respond to specific questions about disclosure, often identifying areas where additional or revised disclosure is necessary.

8. Verification of Factual Statements. C&H will implement verification procedures (commonly referred to as "back-up books" or "verification notes") for material factual statements in the Prospectus. These procedures involve cross-referencing specific factual claims in the Prospectus — such as market position claims, employee headcount, revenue and margin figures, use of proceeds allocations, patent counts, and construction status — to underlying source documents, third-party reports, or management certificates. Verification procedures serve both as a quality control measure and as documentary evidence supporting the factual predicate for the negative assurance letter.

B. Due Diligence Defense Memorandum

It is the Firm's strong recommendation that C&H maintain a comprehensive "due diligence defense memorandum" (also referred to as a "due diligence binder" or "back-up file") documenting every step of the due diligence process undertaken in connection with the Offering. The defense memorandum should be a contemporaneous record of all due diligence activities, organized both chronologically and by subject matter, and should be updated on a rolling basis as new activities are completed and new documents are reviewed.

The contents of the defense memorandum should include, at a minimum:

• Interview summaries and attendance records for all management interviews;

• Document request lists and responses, including an itemized log of all documents received from Halcyon, Bähr Stein, and other parties;

• Copies of, or references to, all reviewed documents, organized by subject matter category;

• All drafts of the Registration Statement and the Prospectus, with blacklines showing revisions, together with C&H's markup and comments;

• Records of verification procedures, including the verification notes and copies of source documents;

• Copies of all SEC comment letters, response letters, and any related correspondence with the SEC staff;

• Internal analysis memoranda on discrete issues (e.g., FPI status, PFIC analysis, export control compliance, related-party transactions); and

• Copies of or references to all third-party reports, certificates, and opinions received as closing deliverables.

The defense memorandum serves a dual purpose. First, it supports C&H's ability to deliver the negative assurance letter in good faith by providing a documented record that the Firm conducted a thorough due diligence process. Second, it provides a contemporaneous litigation defense record should Section 11 or Section 12(a)(2) claims arise following the Offering. In the event of post-offering securities litigation, the defense memorandum will serve as the primary evidentiary basis for demonstrating the scope and thoroughness of C&H's professional involvement in the preparation of the offering documents.

Audrey Zhou is assigned primary responsibility for the assembly and ongoing maintenance of the defense memorandum. Claire Dempsey will supervise its preparation and review its contents at regular intervals to ensure completeness and accuracy.

C. Due Diligence Timeline Correlation

The due diligence program must be executed in alignment with the overall Offering timeline. The following key milestones govern the pacing and sequencing of due diligence activities:

The engagement team should note that the period between the confidential submission (April 14, 2026) and public filing (June 8, 2026) will be occupied primarily by SEC comment letter responses and prospectus revisions, during which time the due diligence program should be supplemented and updated as warranted by changes in the disclosure. The period between effectiveness (June 22, 2026) and pricing (July 1, 2026) is critical for bring-down procedures, as counsel must confirm that no developments have occurred since the date of effectiveness that would render the Registration Statement or Prospectus materially misleading.

V. Form and Content of the Negative Assurance Letter

A. Addressees

The negative assurance letter will be addressed to Westbridge Securities LLC, as representative of the several Underwriters, Pinnacle Morgan & Co., Inc., Andover Barcliffe Group Inc., and Northpointe Capital LLC. Each addressee will be specifically named in the letter, reflecting their respective roles in the underwriting syndicate.

An additional question to be confirmed is whether the letter should also be addressed to V&K as counsel to the Underwriters. In certain transactions, underwriters' counsel requests that the issuer's counsel's negative assurance letter be delivered directly to underwriters' counsel in addition to the Underwriters themselves, to facilitate V&K's own review and reliance. This question should be discussed with Martin Ashford at V&K during the initial negotiation of the letter's scope and form.

B. Introductory Paragraphs

The introductory paragraphs of the letter will contain the following elements:

• Identification of C&H as United States securities counsel to Halcyon Semiconductor Aktiengesellschaft in connection with the Registration Statement on Form F-1 (File No. 333-[●]) filed with the SEC under the Securities Act, and the offering of [●] ADSs (each ADS representing two (2) ordinary shares (Stammaktien), par value €1.00 per share, of the Company);

• A statement describing the scope of C&H's engagement, including the nature and extent of C&H's participation in the preparation of the Registration Statement and the Prospectus;

• A reference to the Underwriting Agreement dated as of July 1, 2026 (the pricing date) among the Company, the Selling Shareholders, and the several Underwriters, with Westbridge Securities LLC acting as representative;

• A reference to the Prospectus dated [●], as supplemented by any pricing supplement or prospectus supplement; and

• A statement that the letter is being delivered pursuant to Section [●] of the Underwriting Agreement as a condition to the obligations of the Underwriters to purchase the ADSs.

C. Qualifications and Assumptions

The negative assurance letter will be subject to the following customary qualifications and assumptions, which define the boundaries of C&H's undertaking and make clear the limitations inherent in the letter:

Reliance on Officers' and Directors' Certificates. The letter will state that C&H has relied, without independent verification, on the officer certificates executed by Dr. Friedrich Wendt and Katarina Dalmqvist, the General Counsel/Secretary certificate executed by Wilhelm Ostermann, and the director and officer questionnaires completed by members of the Vorstand and Aufsichtsrat, in each case as to factual matters within the personal knowledge of such officers and directors.

Reliance on Selling Shareholder Certificates. The letter will state that C&H has relied on the selling shareholder certificates executed by Margarethe Wendt on behalf of Rheintal Industrieholding GmbH and Henrik Sørensen on behalf of Kestrel Capital Partners AG, in each case with respect to the accuracy of the Selling Shareholder information contained in the Prospectus.

Reliance on Foreign Counsel Opinions. The letter will state that C&H has relied on the opinions of Bähr Stein Rechtsanwälte, as German issuer counsel, and Prumvane Thornton LLP, as German underwriters' counsel, for all matters of German law, including corporate law, regulatory law, and tax law. C&H expresses no view on matters of German law or the law of any jurisdiction other than the federal law of the United States and the law of the State of New York.

Reliance on Comfort Letters. The letter will state that C&H has relied on the comfort letters from Blackmere & Whitfield LLP and Blackmere & Whitfield GmbH WPG for all financial statements, financial schedules, and specified financial data contained in the Registration Statement and the Prospectus, and that C&H has not independently verified any financial data.

Reliance on Tax Analysis. The letter will note that C&H has relied on the tax analysis and advice of Leonard Cross, Specialist Partner, Tax, in connection with the U.S. federal income tax disclosure and the PFIC analysis, including the preliminary conclusion that the Company is not a PFIC and satisfies the active business exception under the applicable provisions of the Internal Revenue Code.

No Independent Verification. The letter will state that C&H has not independently verified the accuracy or completeness of any financial statements or financial data, and has not conducted any independent investigation of facts or circumstances beyond those arising from C&H's participation in the preparation of the Registration Statement and the Prospectus.

No Obligation to Update. The letter will state that C&H assumes no obligation to update or supplement the letter after the date of its delivery.

Governing Law. The letter will state that it is governed by, and shall be construed in accordance with, the laws of the State of New York, consistent with the governing law provision of the Underwriting Agreement.

D. Negative Assurance Statement

The core operative language of the negative assurance letter will read substantially as follows:

"Based upon and subject to the foregoing, and having regard to legal developments as of the date hereof, we advise you that nothing has come to our attention that causes us to believe that the Registration Statement, as of the date of its effectiveness, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading, or that the Prospectus, as of its date and as of the date hereof, contained or contains any untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading."

Immediately following the operative language, the letter will include an express carve-out for the excluded portions identified in Section III.B above, including financial statements and related notes, financial schedules and statistical data within the scope of the auditors' comfort letters, forward-looking statements and projections covered by the PSLRA safe harbor, expert portions of the Registration Statement, statements attributable to regulatory bodies, German tax disclosure, and German corporate law matters.

The precise formulation of the carve-out language is typically a subject of negotiation with V&K. C&H should aim to maintain broad carve-outs that clearly delineate the boundaries of the Firm's undertaking while satisfying V&K's expectation that the carve-outs are not so expansive as to render the letter meaningless. Vivienne St. Claire should lead these negotiations.

E. Bring-Down Procedures

The negative assurance letter is delivered as of the closing date (July 6, 2026), but the factual predicate for the letter is established through an ongoing process that extends from the commencement of due diligence through closing. To ensure that the letter is current as of the date of delivery, C&H must implement the following bring-down procedures:

Bring-Down at Pricing (July 1, 2026). Immediately prior to or on the pricing date, C&H will conduct a bring-down management call with Dr. Friedrich Wendt, Katarina Dalmqvist, and Wilhelm Ostermann (and such other members of management as may be appropriate). The purpose of the bring-down call is to confirm that: (i) no material adverse change has occurred in the business, financial condition, or results of operations of the Company since the date of effectiveness of the Registration Statement; (ii) no new litigation, regulatory proceedings, or other developments have arisen that would require disclosure in the Prospectus; and (iii) the Prospectus, as supplemented by any pricing supplement, is accurate and complete in all material respects. In addition, C&H will review any changes to the Prospectus since the date of effectiveness, including the incorporation of pricing information and any last-minute revisions.

Bring-Down at Closing (July 6, 2026). On the closing date, C&H will conduct a final bring-down, which may consist of a telephone conference with management or a review of updated officer certificates. The purpose of the closing bring-down is to confirm that no developments have occurred between the pricing date and the closing date that would affect the accuracy or completeness of the Prospectus. Updated officer certificates from Dr. Wendt and Dalmqvist will be received on or prior to closing. Upon completion of the closing bring-down, C&H will deliver the executed negative assurance letter.

Overallotment Option Exercise. The Underwriters have been granted an option, exercisable for up to 30 days following the pricing date (expiration July 31, 2026), to purchase up to 3,210,000 additional ADSs. If the overallotment option is exercised, C&H must confirm whether a supplemental bring-down or bring-down letter is required for the option closing date. This is an open issue to be resolved in coordination with V&K and the Underwriters, and will depend on the terms of the Underwriting Agreement. If a supplemental bring-down is required, C&H will need to repeat the bring-down management call and confirm the absence of any material developments between the initial closing date and the option closing date.

VI. Coordination with Other Closing Deliverables

A. Comfort Letters from Blackmere & Whitfield

The auditors' comfort letters are among the most important closing deliverables and are directly complementary to C&H's negative assurance letter. The comfort letters will be delivered by Blackmere & Whitfield LLP (Graham Templeton, Engagement Partner, New York) and Blackmere & Whitfield GmbH Wirtschaftsprüfungsgesellschaft (Dieter Kaufmann, Lead Partner, Munich) in accordance with the professional standards set forth in SAS No. 72 (Letters for Underwriters and Certain Other Requesting Parties) and ISAE 3000 (International Standard on Assurance Engagements).

The comfort letters will cover the following:

• The audited consolidated financial statements of the Company prepared in accordance with IFRS for the fiscal years ended December 31, 2023 (revenue: €3,214 million; net income: €482 million), December 31, 2024 (revenue: €3,508 million; net income: €541 million), and December 31, 2025 (revenue: €3,820 million, unaudited; net income: €612 million, unaudited);

• Capsule financial information for interim periods, if applicable;

• Specified financial data appearing in the text of the Prospectus, including revenue figures, EBITDA, margins, per-share data, and other statistical financial information; and

• Negative assurance with respect to any subsequent changes in specified financial items during the "change period" (the period from the latest balance sheet date through a date no more than 135 days prior to the filing or effective date of the Registration Statement).

C&H's negative assurance letter will expressly disclaim coverage of all matters addressed by the comfort letters. This carve-out is critical and non-negotiable, as it reflects the fundamental division of professional responsibility between counsel and auditors. C&H will coordinate the circle-up timing with Blackmere & Whitfield to ensure that the comfort letters and the negative assurance letter are delivered concurrently at closing. C&H previously circulated a draft comfort letter request to Blackmere & Whitfield, which is being finalized in coordination with V&K.

B. Legal Opinions

Multiple legal opinions will be delivered at closing, in addition to C&H's negative assurance letter. The coordination of these opinions is essential to ensure that the closing deliverable package is comprehensive and that coverage gaps do not exist. The principal legal opinions are as follows:

• C&H Opinion on Validity of ADSs: C&H will deliver a separate legal opinion (distinct from the negative assurance letter) regarding the valid issuance of the ADSs and the authorization of the deposit agreement with Meridian Trust Company, N.A.;

• C&H Tax Opinion: Leonard Cross will deliver a tax opinion on the U.S. federal income tax consequences of the acquisition, ownership, and disposition of ADSs by U.S. holders, including the PFIC analysis;

• Bähr Stein Opinion: Bähr Stein Rechtsanwälte will deliver an opinion on German corporate law matters, including the validity of the underlying ordinary shares (Stammaktien) under German law, the corporate authorizations for the issuance of up to 30,000,000 new ordinary shares under the authorized capital (genehmigtes Kapital), the valid exclusion of preemptive rights (Bezugsrechte) in connection with the Offering, and the registration of the new shares in the commercial register;

• Prumvane Thornton Opinion: Prumvane Thornton LLP (Dr. Stefan Braun, Partner) will deliver an opinion on German law matters for the benefit of the Underwriters; and

• V&K Negative Assurance Letter: V&K will deliver its own negative assurance letter as counsel to the Underwriters, based on V&K's independent participation in the due diligence process and the preparation of the Registration Statement and Prospectus.

C. Certificates

The following certificates will be delivered at closing and will serve as part of the documentary foundation supporting C&H's negative assurance letter:

• Officer's Certificate: Executed jointly by Dr. Friedrich Wendt (CEO) and Katarina Dalmqvist (CFO), certifying as to the accuracy of statements in the Registration Statement and Prospectus and the absence of any material adverse change in the Company's business, financial condition, or results of operations since the date of the latest financial statements;

• Secretary / General Counsel Certificate: Executed by Wilhelm Ostermann, confirming the Vorstand and Aufsichtsrat resolutions authorizing the Offering, the current organizational documents of the Company, and such other corporate matters as the Underwriters may reasonably require; and

• Selling Shareholder Certificates: Executed by Margarethe Wendt on behalf of Rheintal Industrieholding GmbH and Henrik Sørensen on behalf of Kestrel Capital Partners AG, certifying as to the accuracy of the information regarding the Selling Shareholders contained in the Prospectus and the authority of the Selling Shareholders to sell their respective ADSs.

D. Closing Checklist Cross-Reference

C&H's negative assurance letter will be designated as Item [●] on the comprehensive closing checklist maintained by the engagement team. The closing checklist is the master tracking document for all closing deliverables and must be updated regularly to reflect the status of each item. C&H will coordinate status tracking with Angela Moretti at Crestfield Transfer Services (transfer agent) and Patricia Novak at Meridian Trust Company, N.A. (depositary) to ensure that settlement logistics are aligned with the closing timeline. The closing checklist should be circulated to all working group members no later than four weeks prior to the anticipated closing date.

VII. Documentation and Record-Keeping Requirements

A. Back-Up Binder Contents

The back-up binder (also referred to as the "due diligence file" or "Section 11 defense file") is the single most important internal record generated by the engagement team in connection with the Offering. It serves as the comprehensive contemporaneous record of the Firm's due diligence activities and provides the evidentiary foundation for the negative assurance letter. The following categories of documents must be compiled in the back-up binder:

1. Due Diligence Memoranda. A complete set of internal due diligence memoranda addressing each category of the due diligence review, including:

• Corporate/organizational due diligence memorandum (organizational structure, governance, capital structure, shareholder agreements);

• Material contracts due diligence memorandum (summary and analysis of all material contracts reviewed);

• intellectual property due diligence memorandum (patents, trademarks, licenses, trade secrets);

• Litigation and regulatory proceedings due diligence memorandum (pending, threatened, and concluded matters);

• Environmental and manufacturing due diligence memorandum (environmental permits, compliance history, manufacturing facility conditions);

• Employee benefits and compensation due diligence memorandum (benefit plans, ESOT structure, executive compensation);

• Related-party transactions due diligence memorandum (al

MEMORANDUM
PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT
TO: Vivienne St. Claire, Responsible Partner, Capital Markets Robert Adeyemi, Billing Partner, Capital Markets
FROM: Claire Dempsey, Lead Associate, Capital Markets
CC: Audrey Zhou, Working Associate, Capital Markets Leonard Cross, Specialist Partner, Tax
DATE: January 30, 2026
RE: Framework for Calderwood & Harkness LLP Negative Assurance Letter and 10b-5 Disclosure Letter — Halcyon Semiconductor AG Level III ADR Initial Public Offering
MATTER NO.: 1032-00003
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I. Purpose and Executive Summary
This memorandum establishes the internal framework, scope, methodology, and factual predicate for Calderwood & Harkness LLP's ("C&H" or the "Firm") delivery of a negative assurance letter (commonly referred to as a "10b-5 letter" or "10b-5 disclosure letter") to the underwriting syndicate in connection with the initial public offering (the "Offering") of American Depositary Shares ("ADSs") of Halcyon Semiconductor Aktiengesellschaft ("Halcyon" or the "Company"). Specifically, the Firm will deliver:
(a) a negative assurance letter addressed to the underwriting syndicate — consisting of Westbridge Securities LLC (lead left bookrunner), Pinnacle Morgan & Co., Inc. (joint bookrunner), Andover Barcliffe Group Inc. (joint bookrunner), and Northpointe Capital LLC (co-manager) (collectively, the "Underwriters"); and
(b) such letter to be delivered at the closing of the Offering (target closing and settlement date: July 6, 2026, T+2 from pricing target of July 1, 2026) as a condition to the Underwriters' obligations under the underwriting agreement.
The negative assurance letter will be delivered pursuant to the conditions to closing set forth in the underwriting agreement (the "Underwriting Agreement"), which will be governed by the laws of the State of New York, among Halcyon Semiconductor Aktiengesellschaft, the selling shareholders — Rheintal Industrieholding GmbH ("Rheintal") and Kestrel Capital Partners AG ("Kestrel") (together, the "Selling Shareholders") — and the several Underwriters, with Westbridge Securities LLC acting as representative of the several Underwriters (in such capacity, the "Representative").
The negative assurance letter is a customary closing deliverable in registered public offerings under the Securities Act of 1933, as amended (the "Securities Act"), and serves as a key element of the Underwriters' due diligence defense under Sections 11 and 12(a)(2) of the Securities Act. The letter provides comfort to the Underwriters that, based on the Firm's professional participation in the preparation of the registration statement and the prospectus, and subject to stated qualifications and limitations, nothing has come to the Firm's attention that causes it to believe that the offering documents contain a material misstatement or omission. While the letter does not constitute a guarantee of accuracy nor serve as a substitute for the Underwriters' own independent due diligence, it is an essential component of the closing mechanics and is invariably required by underwriting syndicates in transactions of this nature and magnitude.
The Registration Statement will be filed on Form F-1 under the Securities Act (the "Registration Statement"), registering ADSs, each representing two (2) ordinary shares (Stammaktien) of Halcyon, par value €1.00 per share, for listing on the Nasdaq Global Select Market under the ticker symbol "HCYN." The Company qualifies as a foreign private issuer ("FPI") under Rule 3b-4 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and the Registration Statement will avail itself of certain accommodations available to FPIs under the Securities Act and Exchange Act, including financial statements prepared in accordance with International Financial Reporting Standards ("IFRS") as issued by the International Accounting Standards Board without reconciliation to U.S. GAAP.
The Offering is structured to include targeted gross proceeds of approximately $900,000,000 through the offering of 21,400,000 ADSs in the base deal — consisting of 15,000,000 ADSs issued by the Company in the primary offering (representing 30,000,000 newly issued ordinary shares) and 6,400,000 ADSs offered by the Selling Shareholders in the secondary offering (representing 12,800,000 existing ordinary shares) — together with an overallotment option granted to the Underwriters for up to 3,210,000 additional ADSs (representing 6,420,000 additional ordinary shares), exercisable for up to 30 days following pricing.
It should be noted that Varen & Kessler LLP ("V&K"), acting through Martin Ashford, Partner, and Priya Ranganathan, Senior Associate, serves as United States counsel to the Underwriters. V&K will independently evaluate the scope and sufficiency of C&H's negative assurance letter. C&H should expect that V&K will negotiate the language, qualifications, and conditions of the letter, as is customary in transactions of this type. The Firm's engagement team should anticipate and prepare for negotiation sessions with V&K regarding the scope of the letter, the adequacy of the factual predicate, and any additional conditions or carve-outs that V&K may request on behalf of the Underwriters.
This memorandum is organized to address: (i) the legal standard and basis for the negative assurance letter; (ii) the scope of the letter and sections covered and excluded; (iii) the due diligence activities forming the factual predicate; (iv) the form and content of the letter; (v) coordination with other closing deliverables; (vi) documentation and record-keeping requirements; (vii) risk considerations and limitations; and (viii) team responsibilities and next steps.
II. Legal Standard and Basis for the Negative Assurance Letter
A. Nature of the 10b-5 Letter
The negative assurance letter, colloquially referred to as a "10b-5 letter," is a statement by issuer's counsel that, based on counsel's participation in the preparation of the Registration Statement on Form F-1 and the prospectus included therein (the "Prospectus"), and subject to stated qualifications and limitations, nothing has come to the attention of the Firm that causes it to believe that:
(i) the Registration Statement, as of the date of its effectiveness, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading; or
(ii) the Prospectus, as of its date and as of the closing date, contained or contains any untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.
It is critical that the engagement team understand the precise nature of this undertaking and its inherent limitations. The negative assurance letter is fundamentally different from an affirmative legal opinion on compliance with the Securities Act or any other body of law. It is not a guarantee of accuracy, completeness, or legal compliance. Nor does it constitute an independent investigation or audit of the facts and circumstances underlying the disclosure contained in the Registration Statement and the Prospectus. Rather, the letter is a report by counsel on the results of counsel's professional involvement in the preparation of the offering documents — a statement that, in the course of performing its customary role as securities counsel, no information came to the Firm's attention that would cause it to believe that the disclosure was materially deficient.
The distinction between the negative assurance letter and the role of auditors is particularly important. Counsel is not conducting an audit or review of financial information; counsel does not possess the professional qualifications to do so. The letter expressly disclaims reliance on financial data, which is the domain of the Company's independent registered public accounting firm, Blackmere & Whitfield LLP and its affiliated German Wirtschaftsprüfungsgesellschaft. Similarly, counsel does not independently verify the accuracy of every factual assertion in the Prospectus, though counsel does conduct verification procedures for material factual claims as part of its due diligence program.
The letter's value lies in the disciplinary function it serves: by requiring counsel to deliver the letter as a closing condition, the offering process creates powerful incentives for counsel to conduct thorough due diligence and to insist on complete and accurate disclosure throughout the drafting process. The letter thus serves as both a professional undertaking and a quality assurance mechanism for the benefit of the Underwriters and, ultimately, investors.
B. Statutory Framework
The negative assurance letter derives its significance from the federal securities law liability framework applicable to registered public offerings. The principal statutory provisions are summarized below.
Section 11 of the Securities Act. Section 11 imposes strict liability on the issuer for material misstatements or omissions in the registration statement at the time of its effectiveness. Unlike the issuer, underwriters are not subject to strict liability under Section 11 but instead may assert a "due diligence" defense under Section 11(b)(3)(A). To establish this defense, an underwriter must demonstrate that, after reasonable investigation, it had reasonable ground to believe, and did believe, that the statements in the registration statement were true and that there was no omission to state a material fact required to be stated therein or necessary to make the statements therein not misleading. The standard of reasonableness is that required of a prudent person in the management of his own property. The negative assurance letter serves as one evidentiary component of the underwriters' reasonable investigation, though it is not sufficient standing alone to establish the defense.
Section 12(a)(2) of the Securities Act. Section 12(a)(2) provides a right of rescission or damages to purchasers who acquire securities by means of a prospectus or oral communication that contains an untrue statement of a material fact or omits to state a material fact necessary in order to make the statements, in the light of the circumstances under which they were made, not misleading. A due diligence defense is available to sellers (including underwriters) who can demonstrate that they did not know, and in the exercise of reasonable care could not have known, of the misstatement or omission. The negative assurance letter supports this defense in a manner analogous to its role under Section 11.
Rule 10b-5 under the Exchange Act. Rule 10b-5 is the general anti-fraud provision promulgated under Section 10(b) of the Exchange Act, which prohibits fraudulent or deceptive conduct in connection with the purchase or sale of securities, including the making of any untrue statement of a material fact or any omission of a material fact necessary in order to make the statements made, in the light of the circumstances under which they were made, not misleading. Although the letter is colloquially called a "10b-5 letter," it is important to recognize that the letter does not constitute an opinion on Rule 10b-5 liability per se. Rule 10b-5 liability requires a showing of scienter (intentional or reckless conduct), which is a distinct element not addressed by the negative assurance letter. Rather, the letter addresses the disclosure standards — materiality, truthfulness, and completeness of statements — that parallel Rule 10b-5's substantive requirements.
ABA TriBar Opinion Committee and Market Practice. The form and content of negative assurance letters have developed over decades of market practice and have been the subject of extensive commentary by the American Bar Association's TriBar Opinion Committee and its successor committees. The TriBar Committee's 2004 report and subsequent updates provide guidance on the scope of the factual predicate necessary to support a negative assurance letter, the appropriate qualifications and limitations, and the relationship between the letter and the broader due diligence program. For cross-border ADR IPOs by foreign private issuers, market practice recognizes the need for coordination with local counsel and appropriate reliance on foreign counsel opinions for matters outside the scope of U.S. securities counsel's expertise. C&H's letter will be prepared in accordance with these principles and with prevailing market practice for Level III ADR IPOs.
C. Significance for Underwriters' Due Diligence Defense
The Underwriters — Westbridge, Pinnacle Morgan, Andover Barcliffe, and Northpointe — rely on the negative assurance letter as one component of their "reasonable investigation" defense under Section 11(b)(3). The Supreme Court's decision in Escott v. BarChris Construction Corp., 283 F. Supp. 643 (S.D.N.Y. 1968), and its progeny establish that the scope of reasonable investigation required of underwriters is greater than that required of outside directors or other non-expert participants, reflecting the underwriters' gatekeeper role in the capital markets. Accordingly, the Underwriters' due diligence program must be comprehensive and well-documented.
The negative assurance letter alone does not establish the due diligence defense. It must be supported by the totality of the Underwriters' due diligence program, including, without limitation:
• Management interviews conducted by the Underwriters and their counsel (V&K);
• Comfort letters from Blackmere & Whitfield LLP/GmbH WPG covering financial statements and specified financial data;
• Legal opinions from German issuer counsel (Bähr Stein Rechtsanwälte) and German underwriters' counsel (Prumvane Thornton LLP);
• Review of corporate records, material contracts, and regulatory filings;
• Independent research on industry conditions and competitive dynamics;
• Officer and director certificates; and
• Any additional diligence activities undertaken by the Underwriters or V&K.
It should further be noted that V&K, as counsel to the Underwriters, will also deliver its own negative assurance letter. The two letters — C&H's as issuer's counsel and V&K's as underwriters' counsel — are complementary and together provide the documentary foundation for the Underwriters' disclosure-related due diligence. V&K's letter will be based on V&K's own independent participation in the preparation and review of the Registration Statement and Prospectus, and V&K will conduct its own due diligence activities to support its letter. The existence of V&K's letter does not diminish the importance or scope of C&H's letter; rather, the two letters reflect different vantage points and different professional involvement in the offering process.
III. Scope of the Negative Assurance Letter
A. Documents Covered
The negative assurance letter is expected to cover the following documents:
Registration Statement on Form F-1. The letter will cover the Registration Statement on Form F-1 filed with the Securities and Exchange Commission (the "SEC"), including all amendments thereto (Amendment No. 1 target: May 26, 2026), through the date of declaration of effectiveness by the SEC (target: June 22, 2026). This includes all exhibits to the Registration Statement to the extent they constitute part of the registration statement for purposes of Section 11.
Prospectus. The letter will cover the Prospectus included in the Registration Statement, including any prospectus supplements, the preliminary prospectus (the "Red Herring"), and any final prospectus filed pursuant to Rule 424(b) under the Securities Act. The negative assurance statement with respect to the Prospectus will address the Prospectus both as of its date and as of the closing date (July 6, 2026).
Registration Statement on Form F-6. The Registration Statement on Form F-6, which registers the ADSs evidenced by American Depositary Receipts ("ADRs") issued by Meridian Trust Company, N.A. as depositary (the "Depositary"), presents a threshold scope question. Form F-6 is a registration statement for the ADSs themselves and typically contains limited disclosure, primarily the deposit agreement and related forms. It is the Firm's recommendation that the scope of the negative assurance letter be limited to the Registration Statement on Form F-1 and the Prospectus included therein, with the Form F-6 addressed only insofar as it incorporates by reference or is part of the F-1 filing package. This recommendation is based on the fact that the Form F-6 is essentially a mechanical registration of the ADSs and does not contain the type of substantive disclosure that is the subject of the negative assurance letter. This scope limitation should be confirmed with Vivienne St. Claire and negotiated with V&K.
Free Writing Prospectuses and Issuer Free Writing Prospectuses. To the extent that C&H is involved in the preparation of any free writing prospectus or issuer free writing prospectus used in connection with the Offering, as defined in Rule 164 and Rule 433 under the Securities Act, the letter may extend to such materials. The scope of coverage for any free writing prospectus should be determined on a case-by-case basis depending on the nature and extent of C&H's involvement in its preparation.
Road Show Materials. If C&H is involved in the preparation of road show materials — including any electronic road show presentation — the letter may need to address such materials. The extent of coverage will depend on the nature of C&H's participation and whether the materials constitute free writing prospectuses subject to filing requirements. This issue should be discussed at the organizational meeting and with V&K.
B. Sections/Portions Expressly Excluded from Negative Assurance
The negative assurance letter will expressly exclude the following portions of the Registration Statement and the Prospectus from its coverage:
Financial Statements and Related Notes. The audited consolidated financial statements of the Company for the fiscal years ended December 31, 2023, December 31, 2024, and December 31, 2025, and the notes thereto, as audited or reviewed by Blackmere & Whitfield, are excluded. These financial statements are covered by the auditors' reports and by the comfort letters delivered pursuant to SAS No. 72 (Letters for Underwriters and Certain Other Requesting Parties) and ISAE 3000 (International Standard on Assurance Engagements). C&H lacks the professional qualifications to address the accuracy of financial statements and accounting disclosures.
Financial Schedules and Statistical Data. Financial schedules and statistical data derived from the Company's accounting records are excluded to the extent such data falls within the scope of the auditors' comfort letters. This includes, without limitation, tables of selected financial data, ratio calculations, and financial data presented in the text of the Prospectus that has been "circled" or "tick-marked" for comfort letter coverage.
Forward-Looking Statements and Projections. Forward-looking statements and projections that are identified as such and that fall within the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 ("PSLRA") and the Securities Act are excluded from the scope of the negative assurance letter. The Prospectus will contain extensive forward-looking statements regarding the Company's strategic plans, anticipated capital expenditures (including Fab 3 expansion), projected market opportunities, and expected financial performance, all of which will be accompanied by appropriate cautionary language identifying important factors that could cause actual results to differ materially.
Expert Portions. Any portions of the Registration Statement or the Prospectus made on the authority of, or constituting the report of, an expert — including the auditors' reports of Blackmere & Whitfield and any geological, engineering, or other technical reports — are excluded. Based on current information, no geological or engineering reports are expected to be included in the Registration Statement for this Offering, but this exclusion is included as a standard protective measure.
Statements of Regulatory Bodies. Statements made on the authority of the SEC, the Nasdaq Stock Market LLC, the German Federal Financial Supervisory Authority (Bundesanstalt für Finanzdienstleistungsaufsicht or "BaFin"), or other regulatory bodies are excluded from the scope of negative assurance.
German Tax Disclosure. German tax disclosure in the Prospectus, to the extent prepared by or attributable to Bähr Stein Rechtsanwälte in its capacity as German tax counsel to the Company, is excluded. The German statutory withholding tax rate of 26.375% (including solidarity surcharge) and the applicable treaty rate of 15% for qualified U.S. holders are matters of German tax law outside the scope of C&H's professional competence.
German Corporate Law Matters. All matters of German corporate law, including the validity of the ordinary shares under German law, the authority of the Company's management board (Vorstand) and supervisory board (Aufsichtsrat) to approve the Offering, and compliance with German securities regulations, are within the province of Bähr Stein Rechtsanwälte as German issuer counsel and are excluded from C&H's negative assurance letter.
C. Sections Requiring Special Attention
The following sections of the Prospectus present areas of heightened complexity, materiality, or risk and will require the engagement team's focused attention during the due diligence and drafting process:
Risk Factors. The Prospectus will contain a comprehensive risk factor section addressing, among other things: semiconductor industry cyclicality and competitive dynamics; risks related to the Company's silicon carbide (SiC) and gallium nitride (GaN) technology platforms; operational risks associated with the Company's manufacturing facilities in Munich, Dresden (Fab 2 and Fab 3 under construction), and Brno; risks related to the Company's operations in the People's Republic of China through Halcyon Shanghai Semiconductor Co., Ltd.; risks associated with dual listing on Nasdaq and the Frankfurt Stock Exchange; the Company's status as a foreign private issuer; passive foreign investment company ("PFIC") risk; foreign currency fluctuations between the euro, U.S. dollar, Chinese renminbi, and Czech koruna; and risks related to export controls (Export Administration Regulations / International Traffic in Arms Regulations) and international sanctions regimes. The risk factor section is among the most closely scrutinized portions of the Prospectus for purposes of both SEC review and the due diligence defense, and the engagement team must ensure that identified risks are disclosed with sufficient specificity and candor.
Business Description. The business description must accurately present Halcyon's operations, including its workforce of approximately 8,400 employees, its revenue of €3.82 billion for fiscal year 2025 (unaudited), its EBITDA of €1.069 billion (28.0% margin), and its competitive positioning in the global power semiconductor market. Claims regarding market position, technology leadership, and competitive advantages must be verified against independent source materials where available.
Use of Proceeds. The Prospectus will disclose the Company's intended use of the net proceeds from the Offering, currently estimated as follows: approximately $280 million for the expansion of Fab 3 in Dresden; approximately $140 million for GaN research and development programs; approximately $100 million for repayment of amounts outstanding under the Company's revolving credit facility; and the balance of approximately $87.95 million for general corporate purposes. Each use of proceeds allocation must be consistent with management's representations and Board approvals and must be presented with appropriate flexibility language where final allocations are subject to management's discretion.
Capitalization and Dilution. The Prospectus will present the Company's capitalization and dilution on both a pre-offering and post-offering basis. The Company currently has 215,000,000 ordinary shares outstanding; following the issuance of 30,000,000 new ordinary shares in the primary offering, the Company will have approximately 245,000,000 ordinary shares outstanding (prior to any exercise of the overallotment option). The ADS-to-ordinary share ratio is 1:2 (each ADS represents two ordinary shares). Dilution calculations must be reviewed for mathematical accuracy and consistency with the financial statements.
Related-Party Transactions. The Prospectus must disclose the Company's transactions with related parties, including Rheintal Industrieholding GmbH, which is controlled by the Wendt family. Margarethe Wendt, the principal of Rheintal, is the sister of the Company's Chief Executive Officer, Dr. Friedrich Wendt. Rheintal holds 22.3% of the Company's pre-IPO ordinary shares and is selling shares representing 4,250,000 ADSs (8,500,000 ordinary shares) in the secondary offering. Following the Offering, Rheintal's ownership will be reduced to approximately 16.1% of the outstanding ordinary shares (assuming no exercise of the overallotment option). Any ongoing commercial arrangements, management agreements, or other transactions between the Company and Rheintal must be fully disclosed and reviewed for compliance with Item 7.B of Form 20-F.
Selling Shareholder Disclosure. In addition to Rheintal, Kestrel Capital Partners AG — a private equity firm managed by Henrik Sørensen — is selling shares representing 2,150,000 ADSs (4,300,000 ordinary shares). Kestrel holds 9.7% of the Company's pre-IPO ordinary shares, and its ownership will be reduced to approximately 6.8% post-Offering. The disclosure regarding the Selling Shareholders' ownership, selling motivations, and any agreements or arrangements with the Company must be verified.
Description of ADSs and Deposit Agreement Terms. The Prospectus will include a description of the ADSs, the terms of the deposit agreement with Meridian Trust Company, N.A., and the rights of ADS holders. This section must accurately reflect the deposit agreement and distinguish the rights of ADS holders from the rights of ordinary shareholders under German law.
Management and Supervisory Board. The Prospectus will disclose the composition of the Company's Vorstand and Aufsichtsrat, including: Dr. Friedrich Wendt, Chief Executive Officer (Vorstandsvorsitzender); Katarina Dalmqvist, Chief Financial Officer; Dr. Marcus Helder, Chief Technology Officer; Ingrid Baumann, Chief Operating Officer; Wilhelm Ostermann, General Counsel and Company Secretary; and Prof. Dr. Anneliese Voss, Chair of the Supervisory Board. Biographical information, compensation data, and any relationships or transactions requiring disclosure must be verified through director and officer questionnaires.
Lock-Up Disclosure. The Prospectus will describe the 180-day lock-up period from the pricing date (July 1, 2026) applicable to the Company, the Selling Shareholders, and the Company's officers and directors, with Westbridge Securities LLC serving as the lock-up consent agent. The lock-up terms must be accurately described and consistent with the lock-up agreements to be executed by the relevant parties.
Taxation Section. The U.S. federal income tax consequences section of the Prospectus will be prepared by Leonard Cross. This section will address, among other things, the taxation of dividends and capital gains to U.S. holders of ADSs, the German statutory withholding tax rate of 26.375% (including solidarity surcharge) and the reduced treaty rate of 15% for qualified U.S. holders under the U.S.-Germany income tax treaty, and the PFIC analysis. Based on preliminary review, Leonard Cross has reached the preliminary conclusion that the Company is not a PFIC, as it satisfies the active business exception. The PFIC analysis is of particular importance given the Company's substantial cash position and the potential for passive income generated by investment holdings. This analysis must be finalized and documented in a separate PFIC memorandum prior to first draft circulation.
IV. Factual Predicate — Due Diligence Process
A. Due Diligence Activities Forming the Basis for Negative Assurance
The integrity and credibility of C&H's negative assurance letter depend entirely on the thoroughness and quality of the due diligence process that underlies it. The Firm cannot deliver the letter in good faith unless it has conducted a comprehensive due diligence program sufficient to establish the factual predicate for the negative assurance statement. The following categories of due diligence activity must be completed prior to delivery of the letter:
1. Document Review. C&H will conduct a comprehensive review of the Company's corporate organizational documents, material contracts, intellectual property portfolio documentation, litigation files, regulatory filings, insurance policies, employee benefit plan documents (including the Employee Share Ownership Trust, which holds approximately 3.1% of the Company's ordinary shares, or 6,665,000 shares), environmental permits, and related-party transaction documentation. The scope of document review is defined by the comprehensive due diligence request list circulated to Halcyon and Bähr Stein Rechtsanwälte, which covers the following categories in detail:
• Corporate organizational documents, including the Company's articles of association (Satzung), Commercial Register extracts from the Handelsregister maintained at the Amtsgericht München (registration number HRB 217458), minutes of meetings of the Vorstand, Aufsichtsrat, and Hauptversammlung (general shareholders' meeting), and shareholder agreements;
• All material contracts to which the Company or any of its subsidiaries is a party, including customer contracts, supply agreements, licensing agreements, joint venture agreements, real property leases, credit facilities, and any contracts that would be required to be filed as exhibits to the Registration Statement under Item 601 of Regulation S-K (as applied to FPIs);
• intellectual property portfolio documentation, including patents, patent applications, trademarks, trade secrets, and any material licensing or cross-licensing arrangements;
• Litigation files, including all pending, threatened, or recently concluded litigation, arbitration, or regulatory proceedings involving the Company or any of its subsidiaries;
• Regulatory filings with German, EU, U.S., Chinese, Singaporean, and Czech regulatory authorities;
• Insurance policies covering the Company's assets, operations, and officers and directors;
• Employee benefit plan documents and employment agreements for key personnel; and
• Related-party transaction documentation, including all agreements between the Company and Rheintal Industrieholding GmbH, Kestrel Capital Partners AG, or entities controlled by or affiliated with members of the Vorstand or Aufsichtsrat.
2. Management Interviews. C&H will conduct in-person or video conference interviews with the following members of Halcyon's senior management team. These interviews are critical to establishing the factual predicate and ensuring that the engagement team has a thorough understanding of the Company's business, operations, and risk profile:
• Dr. Friedrich Wendt, Chief Executive Officer — corporate strategy, business overview, competitive landscape, market positioning in the global power semiconductor industry, key customer and supplier relationships, and related-party transactions with Rheintal Industrieholding GmbH;
• Katarina Dalmqvist, Chief Financial Officer — financial matters, capital structure and debt obligations, internal controls over financial reporting, disclosure controls and procedures, intended use of proceeds from the Offering, and accounting policies;
• Dr. Marcus Helder, Chief Technology Officer — technology platform and product roadmap, intellectual property portfolio, research and development programs (including GaN and SiC programs), and competitive technology landscape;
• Ingrid Baumann, Chief Operating Officer — manufacturing operations at the Munich headquarters, Dresden (Fab 2 operational and Fab 3 under construction), and Brno facilities, supply chain management, capacity utilization, and construction timeline for Fab 3;
• Wilhelm Ostermann, General Counsel and Company Secretary — pending and threatened litigation, regulatory proceedings, compliance programs (anti-corruption, export controls, sanctions), related-party transactions, and corporate governance structure;
• Additional interviews with divisional management and subsidiary heads — as warranted by the initial due diligence review, including the head of Halcyon Semiconductor USA Inc. in Santa Clara (to cover U.S. operations, customers, and regulatory compliance) and management of Halcyon Shanghai Semiconductor Co., Ltd. (to cover PRC operations, regulatory environment, and data privacy compliance).
Each management interview will be documented in a written interview summary prepared by the attending associates and reviewed by the supervising partner. Interview summaries will include a record of attendees, the date, time, and format of the interview, the topics covered, and any follow-up items identified.
3. Legal and Regulatory Review. C&H will conduct a thorough analysis of the Company's legal and regulatory environment, with particular emphasis on:
• Pending, threatened, or recently concluded litigation, arbitration, or regulatory proceedings;
• Compliance with the sanctions programs administered by the Office of Foreign Assets Control ("OFAC") of the U.S. Department of the Treasury, EU sanctions regulations, and comparable programs administered by other jurisdictions in which the Company operates;
• Compliance with the Foreign Corrupt Practices Act ("FCPA"), the UK Bribery Act 2010, and applicable local anti-corruption laws;
• Compliance with U.S. export control regulations, including the Export Administration Regulations ("EAR") and the International Traffic in Arms Regulations ("ITAR"), which are of critical importance for semiconductor manufacturers — particularly with respect to exports of controlled semiconductor technology and equipment, and especially concerning the Company's operations in China through Halcyon Shanghai Semiconductor Co., Ltd.; and
• Environmental, health, and safety regulatory compliance at the Company's manufacturing facilities.
The export control and sanctions compliance analysis is of heightened importance in this transaction given the current regulatory environment governing semiconductor exports to the PRC and the Company's WFOE structure in Shanghai. C&H will review the Company's export control compliance programs, export license applications and determinations, classification of products under the Commerce Control List, and any instances of potential violations or voluntary self-disclosures.
4. Subsidiary Review. C&H will conduct due diligence on each of the Company's material subsidiaries to confirm the accuracy of the subsidiary disclosure in the Registration Statement and to identify any subsidiary-level risks, liabilities, or regulatory issues that may be material to the Company on a consolidated basis. The material subsidiaries include:
• Halcyon Semiconductor USA Inc. — organized under the laws of the State of Delaware; Employer Identification Number 84-3927561; principal office located in Santa Clara, California; engages in sales, marketing, and applications engineering for the North American market;
• Halcyon Power Solutions GmbH — organized under the laws of Germany; located in Dresden; operates the Company's Fab 2 wafer fabrication facility and oversees construction of Fab 3;
• Halcyon Asia Pacific Pte. Ltd. — organized under the laws of Singapore; serves as the Company's regional headquarters for the Asia-Pacific region (excluding the PRC);
• Halcyon Shanghai Semiconductor Co., Ltd. — organized as a wholly foreign-owned enterprise (WFOE) under the laws of the People's Republic of China; located in Shanghai; engages in semiconductor design, testing, and customer support activities for the Chinese market; and
• Halcyon Automotive Components s.r.o. — organized under the laws of the Czech Republic; located in Brno; engages in manufacturing of automotive-grade power semiconductor modules.
5. Third-Party Reports and Certificates. C&H will review the following third-party reports and certificates that form part of the closing deliverable package and contribute to the factual predicate for the negative assurance letter:
• Comfort letters from Blackmere & Whitfield LLP (Graham Templeton, Engagement Partner, New York) and Blackmere & Whitfield GmbH Wirtschaftsprüfungsgesellschaft (Dieter Kaufmann, Lead Partner, Munich), delivered pursuant to SAS No. 72 and ISAE 3000;
• Legal opinions from Bähr Stein Rechtsanwälte (German issuer counsel) and Prumvane Thornton LLP (German underwriters' counsel; Dr. Stefan Braun, Partner);
• Officer certificates executed by Dr. Friedrich Wendt (CEO) and Katarina Dalmqvist (CFO), certifying as to the accuracy of statements in the Registration Statement and the absence of material adverse changes;
• General Counsel / Secretary certificate from Wilhelm Ostermann, confirming Vorstand and Aufsichtsrat resolutions, organizational documents, and other corporate matters;
• Selling shareholder certificates from Rheintal Industrieholding GmbH (executed by Margarethe Wendt) and Kestrel Capital Partners AG (executed by Henrik Sørensen), confirming the accuracy of the Selling Shareholder information in the Prospectus.
6. Prospectus Drafting Participation. C&H's active participation in all drafting sessions is an essential component of the factual predicate. Through the drafting process, counsel develops a detailed understanding of the disclosure and has the opportunity to identify and address potential misstatements or omissions in real time. The engagement team will participate in all drafting sessions, including the all-parties drafting session scheduled for March 23–24, 2026. C&H will be responsible for the review and revision of all non-financial portions of the Prospectus and will coordinate with Bähr Stein Rechtsanwälte regarding German law disclosure contained in the Prospectus.
7. SEC Comment Letter Responses. C&H will participate in formulating responses to SEC Division of Corporation Finance staff comments on the Registration Statement. Based on typical review timelines for FPI IPOs, the Firm estimates that the first SEC comment letter may be received on or around May 12, 2026, following the confidential submission of the draft Registration Statement on April 14, 2026. Amendment No. 1, incorporating responses to the first round of comments, is targeted for filing on or about May 26, 2026. The comment letter process is an important element of the factual predicate because it requires counsel to analyze and respond to specific questions about disclosure, often identifying areas where additional or revised disclosure is necessary.
8. Verification of Factual Statements. C&H will implement verification procedures (commonly referred to as "back-up books" or "verification notes") for material factual statements in the Prospectus. These procedures involve cross-referencing specific factual claims in the Prospectus — such as market position claims, employee headcount, revenue and margin figures, use of proceeds allocations, patent counts, and construction status — to underlying source documents, third-party reports, or management certificates. Verification procedures serve both as a quality control measure and as documentary evidence supporting the factual predicate for the negative assurance letter.
B. Due Diligence Defense Memorandum
It is the Firm's strong recommendation that C&H maintain a comprehensive "due diligence defense memorandum" (also referred to as a "due diligence binder" or "back-up file") documenting every step of the due diligence process undertaken in connection with the Offering. The defense memorandum should be a contemporaneous record of all due diligence activities, organized both chronologically and by subject matter, and should be updated on a rolling basis as new activities are completed and new documents are reviewed.
The contents of the defense memorandum should include, at a minimum:
• Interview summaries and attendance records for all management interviews;
• Document request lists and responses, including an itemized log of all documents received from Halcyon, Bähr Stein, and other parties;
• Copies of, or references to, all reviewed documents, organized by subject matter category;
• All drafts of the Registration Statement and the Prospectus, with blacklines showing revisions, together with C&H's markup and comments;
• Records of verification procedures, including the verification notes and copies of source documents;
• Copies of all SEC comment letters, response letters, and any related correspondence with the SEC staff;
• Internal analysis memoranda on discrete issues (e.g., FPI status, PFIC analysis, export control compliance, related-party transactions); and
• Copies of or references to all third-party reports, certificates, and opinions received as closing deliverables.
The defense memorandum serves a dual purpose. First, it supports C&H's ability to deliver the negative assurance letter in good faith by providing a documented record that the Firm conducted a thorough due diligence process. Second, it provides a contemporaneous litigation defense record should Section 11 or Section 12(a)(2) claims arise following the Offering. In the event of post-offering securities litigation, the defense memorandum will serve as the primary evidentiary basis for demonstrating the scope and thoroughness of C&H's professional involvement in the preparation of the offering documents.
Audrey Zhou is assigned primary responsibility for the assembly and ongoing maintenance of the defense memorandum. Claire Dempsey will supervise its preparation and review its contents at regular intervals to ensure completeness and accuracy.
C. Due Diligence Timeline Correlation
The due diligence program must be executed in alignment with the overall Offering timeline. The following key milestones govern the pacing and sequencing of due diligence activities:
The engagement team should note that the period between the confidential submission (April 14, 2026) and public filing (June 8, 2026) will be occupied primarily by SEC comment letter responses and prospectus revisions, during which time the due diligence program should be supplemented and updated as warranted by changes in the disclosure. The period between effectiveness (June 22, 2026) and pricing (July 1, 2026) is critical for bring-down procedures, as counsel must confirm that no developments have occurred since the date of effectiveness that would render the Registration Statement or Prospectus materially misleading.
V. Form and Content of the Negative Assurance Letter
A. Addressees
The negative assurance letter will be addressed to Westbridge Securities LLC, as representative of the several Underwriters, Pinnacle Morgan & Co., Inc., Andover Barcliffe Group Inc., and Northpointe Capital LLC. Each addressee will be specifically named in the letter, reflecting their respective roles in the underwriting syndicate.
An additional question to be confirmed is whether the letter should also be addressed to V&K as counsel to the Underwriters. In certain transactions, underwriters' counsel requests that the issuer's counsel's negative assurance letter be delivered directly to underwriters' counsel in addition to the Underwriters themselves, to facilitate V&K's own review and reliance. This question should be discussed with Martin Ashford at V&K during the initial negotiation of the letter's scope and form.
B. Introductory Paragraphs
The introductory paragraphs of the letter will contain the following elements:
• Identification of C&H as United States securities counsel to Halcyon Semiconductor Aktiengesellschaft in connection with the Registration Statement on Form F-1 (File No. 333-[●]) filed with the SEC under the Securities Act, and the offering of [●] ADSs (each ADS representing two (2) ordinary shares (Stammaktien), par value €1.00 per share, of the Company);
• A statement describing the scope of C&H's engagement, including the nature and extent of C&H's participation in the preparation of the Registration Statement and the Prospectus;
• A reference to the Underwriting Agreement dated as of July 1, 2026 (the pricing date) among the Company, the Selling Shareholders, and the several Underwriters, with Westbridge Securities LLC acting as representative;
• A reference to the Prospectus dated [●], as supplemented by any pricing supplement or prospectus supplement; and
• A statement that the letter is being delivered pursuant to Section [●] of the Underwriting Agreement as a condition to the obligations of the Underwriters to purchase the ADSs.
C. Qualifications and Assumptions
The negative assurance letter will be subject to the following customary qualifications and assumptions, which define the boundaries of C&H's undertaking and make clear the limitations inherent in the letter:
Reliance on Officers' and Directors' Certificates. The letter will state that C&H has relied, without independent verification, on the officer certificates executed by Dr. Friedrich Wendt and Katarina Dalmqvist, the General Counsel/Secretary certificate executed by Wilhelm Ostermann, and the director and officer questionnaires completed by members of the Vorstand and Aufsichtsrat, in each case as to factual matters within the personal knowledge of such officers and directors.
Reliance on Selling Shareholder Certificates. The letter will state that C&H has relied on the selling shareholder certificates executed by Margarethe Wendt on behalf of Rheintal Industrieholding GmbH and Henrik Sørensen on behalf of Kestrel Capital Partners AG, in each case with respect to the accuracy of the Selling Shareholder information contained in the Prospectus.
Reliance on Foreign Counsel Opinions. The letter will state that C&H has relied on the opinions of Bähr Stein Rechtsanwälte, as German issuer counsel, and Prumvane Thornton LLP, as German underwriters' counsel, for all matters of German law, including corporate law, regulatory law, and tax law. C&H expresses no view on matters of German law or the law of any jurisdiction other than the federal law of the United States and the law of the State of New York.
Reliance on Comfort Letters. The letter will state that C&H has relied on the comfort letters from Blackmere & Whitfield LLP and Blackmere & Whitfield GmbH WPG for all financial statements, financial schedules, and specified financial data contained in the Registration Statement and the Prospectus, and that C&H has not independently verified any financial data.
Reliance on Tax Analysis. The letter will note that C&H has relied on the tax analysis and advice of Leonard Cross, Specialist Partner, Tax, in connection with the U.S. federal income tax disclosure and the PFIC analysis, including the preliminary conclusion that the Company is not a PFIC and satisfies the active business exception under the applicable provisions of the Internal Revenue Code.
No Independent Verification. The letter will state that C&H has not independently verified the accuracy or completeness of any financial statements or financial data, and has not conducted any independent investigation of facts or circumstances beyond those arising from C&H's participation in the preparation of the Registration Statement and the Prospectus.
No Obligation to Update. The letter will state that C&H assumes no obligation to update or supplement the letter after the date of its delivery.
Governing Law. The letter will state that it is governed by, and shall be construed in accordance with, the laws of the State of New York, consistent with the governing law provision of the Underwriting Agreement.
D. Negative Assurance Statement
The core operative language of the negative assurance letter will read substantially as follows:
"Based upon and subject to the foregoing, and having regard to legal developments as of the date hereof, we advise you that nothing has come to our attention that causes us to believe that the Registration Statement, as of the date of its effectiveness, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading, or that the Prospectus, as of its date and as of the date hereof, contained or contains any untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading."
Immediately following the operative language, the letter will include an express carve-out for the excluded portions identified in Section III.B above, including financial statements and related notes, financial schedules and statistical data within the scope of the auditors' comfort letters, forward-looking statements and projections covered by the PSLRA safe harbor, expert portions of the Registration Statement, statements attributable to regulatory bodies, German tax disclosure, and German corporate law matters.
The precise formulation of the carve-out language is typically a subject of negotiation with V&K. C&H should aim to maintain broad carve-outs that clearly delineate the boundaries of the Firm's undertaking while satisfying V&K's expectation that the carve-outs are not so expansive as to render the letter meaningless. Vivienne St. Claire should lead these negotiations.
E. Bring-Down Procedures
The negative assurance letter is delivered as of the closing date (July 6, 2026), but the factual predicate for the letter is established through an ongoing process that extends from the commencement of due diligence through closing. To ensure that the letter is current as of the date of delivery, C&H must implement the following bring-down procedures:
Bring-Down at Pricing (July 1, 2026). Immediately prior to or on the pricing date, C&H will conduct a bring-down management call with Dr. Friedrich Wendt, Katarina Dalmqvist, and Wilhelm Ostermann (and such other members of management as may be appropriate). The purpose of the bring-down call is to confirm that: (i) no material adverse change has occurred in the business, financial condition, or results of operations of the Company since the date of effectiveness of the Registration Statement; (ii) no new litigation, regulatory proceedings, or other developments have arisen that would require disclosure in the Prospectus; and (iii) the Prospectus, as supplemented by any pricing supplement, is accurate and complete in all material respects. In addition, C&H will review any changes to the Prospectus since the date of effectiveness, including the incorporation of pricing information and any last-minute revisions.
Bring-Down at Closing (July 6, 2026). On the closing date, C&H will conduct a final bring-down, which may consist of a telephone conference with management or a review of updated officer certificates. The purpose of the closing bring-down is to confirm that no developments have occurred between the pricing date and the closing date that would affect the accuracy or completeness of the Prospectus. Updated officer certificates from Dr. Wendt and Dalmqvist will be received on or prior to closing. Upon completion of the closing bring-down, C&H will deliver the executed negative assurance letter.
Overallotment Option Exercise. The Underwriters have been granted an option, exercisable for up to 30 days following the pricing date (expiration July 31, 2026), to purchase up to 3,210,000 additional ADSs. If the overallotment option is exercised, C&H must confirm whether a supplemental bring-down or bring-down letter is required for the option closing date. This is an open issue to be resolved in coordination with V&K and the Underwriters, and will depend on the terms of the Underwriting Agreement. If a supplemental bring-down is required, C&H will need to repeat the bring-down management call and confirm the absence of any material developments between the initial closing date and the option closing date.
VI. Coordination with Other Closing Deliverables
A. Comfort Letters from Blackmere & Whitfield
The auditors' comfort letters are among the most important closing deliverables and are directly complementary to C&H's negative assurance letter. The comfort letters will be delivered by Blackmere & Whitfield LLP (Graham Templeton, Engagement Partner, New York) and Blackmere & Whitfield GmbH Wirtschaftsprüfungsgesellschaft (Dieter Kaufmann, Lead Partner, Munich) in accordance with the professional standards set forth in SAS No. 72 (Letters for Underwriters and Certain Other Requesting Parties) and ISAE 3000 (International Standard on Assurance Engagements).
The comfort letters will cover the following:
• The audited consolidated financial statements of the Company prepared in accordance with IFRS for the fiscal years ended December 31, 2023 (revenue: €3,214 million; net income: €482 million), December 31, 2024 (revenue: €3,508 million; net income: €541 million), and December 31, 2025 (revenue: €3,820 million, unaudited; net income: €612 million, unaudited);
• Capsule financial information for interim periods, if applicable;
• Specified financial data appearing in the text of the Prospectus, including revenue figures, EBITDA, margins, per-share data, and other statistical financial information; and
• Negative assurance with respect to any subsequent changes in specified financial items during the "change period" (the period from the latest balance sheet date through a date no more than 135 days prior to the filing or effective date of the Registration Statement).
C&H's negative assurance letter will expressly disclaim coverage of all matters addressed by the comfort letters. This carve-out is critical and non-negotiable, as it reflects the fundamental division of professional responsibility between counsel and auditors. C&H will coordinate the circle-up timing with Blackmere & Whitfield to ensure that the comfort letters and the negative assurance letter are delivered concurrently at closing. C&H previously circulated a draft comfort letter request to Blackmere & Whitfield, which is being finalized in coordination with V&K.
B. Legal Opinions
Multiple legal opinions will be delivered at closing, in addition to C&H's negative assurance letter. The coordination of these opinions is essential to ensure that the closing deliverable package is comprehensive and that coverage gaps do not exist. The principal legal opinions are as follows:
• C&H Opinion on Validity of ADSs: C&H will deliver a separate legal opinion (distinct from the negative assurance letter) regarding the valid issuance of the ADSs and the authorization of the deposit agreement with Meridian Trust Company, N.A.;
• C&H Tax Opinion: Leonard Cross will deliver a tax opinion on the U.S. federal income tax consequences of the acquisition, ownership, and disposition of ADSs by U.S. holders, including the PFIC analysis;
• Bähr Stein Opinion: Bähr Stein Rechtsanwälte will deliver an opinion on German corporate law matters, including the validity of the underlying ordinary shares (Stammaktien) under German law, the corporate authorizations for the issuance of up to 30,000,000 new ordinary shares under the authorized capital (genehmigtes Kapital), the valid exclusion of preemptive rights (Bezugsrechte) in connection with the Offering, and the registration of the new shares in the commercial register;
• Prumvane Thornton Opinion: Prumvane Thornton LLP (Dr. Stefan Braun, Partner) will deliver an opinion on German law matters for the benefit of the Underwriters; and
• V&K Negative Assurance Letter: V&K will deliver its own negative assurance letter as counsel to the Underwriters, based on V&K's independent participation in the due diligence process and the preparation of the Registration Statement and Prospectus.
C. Certificates
The following certificates will be delivered at closing and will serve as part of the documentary foundation supporting C&H's negative assurance letter:
• Officer's Certificate: Executed jointly by Dr. Friedrich Wendt (CEO) and Katarina Dalmqvist (CFO), certifying as to the accuracy of statements in the Registration Statement and Prospectus and the absence of any material adverse change in the Company's business, financial condition, or results of operations since the date of the latest financial statements;
• Secretary / General Counsel Certificate: Executed by Wilhelm Ostermann, confirming the Vorstand and Aufsichtsrat resolutions authorizing the Offering, the current organizational documents of the Company, and such other corporate matters as the Underwriters may reasonably require; and
• Selling Shareholder Certificates: Executed by Margarethe Wendt on behalf of Rheintal Industrieholding GmbH and Henrik Sørensen on behalf of Kestrel Capital Partners AG, certifying as to the accuracy of the information regarding the Selling Shareholders contained in the Prospectus and the authority of the Selling Shareholders to sell their respective ADSs.
D. Closing Checklist Cross-Reference
C&H's negative assurance letter will be designated as Item [●] on the comprehensive closing checklist maintained by the engagement team. The closing checklist is the master tracking document for all closing deliverables and must be updated regularly to reflect the status of each item. C&H will coordinate status tracking with Angela Moretti at Crestfield Transfer Services (transfer agent) and Patricia Novak at Meridian Trust Company, N.A. (depositary) to ensure that settlement logistics are aligned with the closing timeline. The closing checklist should be circulated to all working group members no later than four weeks prior to the anticipated closing date.
VII. Documentation and Record-Keeping Requirements
A. Back-Up Binder Contents
The back-up binder (also referred to as the "due diligence file" or "Section 11 defense file") is the single most important internal record generated by the engagement team in connection with the Offering. It serves as the comprehensive contemporaneous record of the Firm's due diligence activities and provides the evidentiary foundation for the negative assurance letter. The following categories of documents must be compiled in the back-up binder:
1. Due Diligence Memoranda. A complete set of internal due diligence memoranda addressing each category of the due diligence review, including:
• Corporate/organizational due diligence memorandum (organizational structure, governance, capital structure, shareholder agreements);
• Material contracts due diligence memorandum (summary and analysis of all material contracts reviewed);
• intellectual property due diligence memorandum (patents, trademarks, licenses, trade secrets);
• Litigation and regulatory proceedings due diligence memorandum (pending, threatened, and concluded matters);
• Environmental and manufacturing due diligence memorandum (environmental permits, compliance history, manufacturing facility conditions);
• Employee benefits and compensation due diligence memorandum (benefit plans, ESOT structure, executive compensation);
• Related-party transactions due diligence memorandum (al

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MATTER NO.: 1032-00003

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