PRIVILEGED AND CONFIDENTIAL — ATTORNEY WORK PRODUCT
CALDERWOOD & HARKNESS LLP 1401 K Street NW, Suite 1200 Washington, D.C. 20005
MEMORANDUM
TO: Elliot Nguyen, Lead Associate, Antitrust & Competition Howard Bellamy, Responsible Partner, Antitrust & Competition
FROM: Aaron Liu, Working Associate, Antitrust & Competition (San Francisco Office, 555 California Street, Suite 2700, San Francisco, CA 94104)
DATE: July 10, 2025
RE: Critique of FTC's Proposed Relevant Product Market — "Online Marketplace Platform Services for Third-Party Sellers in the United States"
MATTER: FTC v. Cascade Retail Holdings Inc. et al., Case No. 2:25-cv-01087-RAJ (W.D. Wash.)
MATTER NO.: 1038-00001
CLIENT: Cascade Retail Holdings Inc.
I. EXECUTIVE SUMMARY
This memorandum analyzes the Federal Trade Commission's proposed relevant product market — "online marketplace platform services for third-party sellers in the United States" — as alleged in the FTC's complaint filed June 23, 2025, before the Honorable Richard A. Johannsen, United States District Court for the Western District of Washington, Seattle Division. The purpose of this memorandum is to set forth the analytical framework and evidentiary foundation for challenging the FTC's market definition in the forthcoming opposition to the FTC's motion for a preliminary injunction, and to coordinate the legal arguments with the expert economic analysis being prepared by our retained experts at Brindoval Analytics LLC.
The central thesis of this memorandum is as follows: the FTC's proposed market is artificially narrow and has been gerrymandered to inflate market concentration statistics to levels that would create a structural presumption of illegality under United States v. Philadelphia National Bank, 374 U.S. 321 (1963), and the Horizontal Merger Guidelines. The relevant market, when properly defined to account for commercial realities, demand-side and supply-side substitution, and the two-sided nature of marketplace platforms under Ohio v. Halcyon Corporation, 138 S. Ct. 2274 (2018), should be defined as "all e-commerce retail" or, at minimum, "all online retail channels available to sellers seeking to reach U.S. consumers." Either of these broader — and analytically correct — market definitions eliminates any basis for a structural presumption of illegality.
Under the FTC's narrow market definition, the combined Cascade-Pinnacle share is 38.3% (Cascade at 8.2% plus Pinnacle at 30.1%), with a post-merger Herfindahl-Hirschman Index ("HHI") of 2,856 (reflecting a delta of 495 from a pre-merger HHI of 2,361). These figures exceed the thresholds set forth in the Horizontal Merger Guidelines for presumptively anticompetitive transactions in highly concentrated markets. However, these numbers are an artifact of the FTC's artificially constricted market boundary. Under defendants' proposed broader market encompassing all U.S. e-commerce retail — a market that generated approximately $757 billion in gross merchandise value ("GMV") in 2024 — the combined entity's share is approximately 7.3% (when including Cascade's direct-to-consumer e-commerce GMV alongside marketplace GMV), or approximately 1.9% if measured by marketplace GMV alone ($14.5 billion combined, consisting of $3.1 billion from CascadeMarket and $11.4 billion from Pinnacle). Under either calculation, the combined entity's share falls far below the levels that would support any inference of market power, much less a structural presumption of illegality. The corresponding HHI figures under the broader market are similarly benign and well within the range the Merger Guidelines identify as unconcentrated or only moderately concentrated.
I recommend that this analysis form the foundation of the market definition arguments in the Memorandum in Opposition to the FTC's Motion for Preliminary Injunction (due August 11, 2025) and that these arguments be coordinated promptly with Dr. Priya Ramanathan of Brindoval Analytics LLC for integration into her expert report (due August 18, 2025). Market definition is the dispositive issue in this case. If the Court rejects the FTC's narrow market, the FTC's entire Section 7 theory — including its structural presumption and its theory of competitive harm — collapses.
II. BACKGROUND
A. The Transaction
On March 14, 2025, Cascade Retail Holdings Inc. ("Cascade" or the "Company") and Pinnacle Market Group Inc. ("Pinnacle") executed an Agreement and Plan of Merger (the "Merger Agreement"). The transaction was publicly announced on March 17, 2025. Under the terms of the Merger Agreement, the transaction is structured as an all-cash reverse triangular merger: CRH Merger Sub Inc. ("Merger Sub"), a Delaware corporation and direct, wholly owned subsidiary of Cascade formed solely for the purpose of effecting the merger, will merge with and into Pinnacle, with Pinnacle surviving the merger as a wholly owned subsidiary of Cascade. The separate corporate existence of Merger Sub will cease upon the effective time of the merger.
The aggregate merger consideration is approximately $4.7 billion, calculated as $26.85 per share of Pinnacle common stock multiplied by 175,047,319 shares of Pinnacle common stock outstanding as of the date of the Merger Agreement. The per-share merger consideration of $26.85 represents a premium of approximately 20.4% over Pinnacle's unaffected closing stock price of $22.30 on March 7, 2025, the last full trading day prior to media speculation regarding a potential transaction between the parties.
The transaction is being financed through a combination of Cascade's existing cash reserves and third-party debt financing. Specifically, Cascade will fund the merger consideration from: (i) approximately $1.9 billion in cash on hand from Cascade's balance sheet; (ii) proceeds from a $2.8 billion senior secured Term Loan B facility to be provided by Whitmore National Bank, N.A., pursuant to a commitment letter dated March 12, 2025 (the "Debt Commitment Letter"); and (iii) a $500 million revolving credit facility (undrawn at close and available for working capital and general corporate purposes). The Debt Commitment Letter contains customary conditions, including the absence of a material adverse effect with respect to Pinnacle, the accuracy of representations and warranties in all material respects, and the delivery of customary closing documentation.
The parties filed the required Hart-Scott-Rodino Antitrust Improvements Act ("HSR Act") notification and report forms with the FTC and the Antitrust Division of the U.S. Department of Justice on April 2, 2025 (Transaction No. HSR-20250402-0347). On May 7, 2025, the FTC issued a Request for Additional Information and Documentary Material (the "Second Request") to both Cascade and Pinnacle (File No. 251-0089). Both parties certified substantial compliance with the Second Request on June 10, 2025. Rather than awaiting the expiration of the Second Request waiting period, the FTC moved swiftly to file suit, as discussed in Section II.C below.
The Merger Agreement provides for an outside date (the "Outside Date") of March 14, 2026, which is automatically extended to June 14, 2026, if the sole remaining unsatisfied closing condition as of March 14, 2026 is the receipt of required antitrust clearances or the absence of a governmental order or injunction prohibiting the consummation of the merger. The Merger Agreement further provides for a reverse termination fee of $282 million (approximately 6% of the aggregate deal value), payable by Cascade to Pinnacle in the event the Merger Agreement is terminated due to the failure to obtain required regulatory approvals or the issuance of a final, non-appealable governmental order prohibiting the merger. Pinnacle is obligated to pay a company termination fee of $164.5 million (approximately 3.5% of the aggregate deal value) in the event the Merger Agreement is terminated under specified circumstances, including a termination by Pinnacle in connection with a superior proposal.
B. The Parties
Cascade Retail Holdings Inc. Cascade is a corporation organized and existing under the laws of the State of Delaware, with its principal executive offices located at 2200 Westlake Avenue North, Suite 3400, Seattle, Washington 98109. Cascade's common stock is listed and traded on the Nasdaq Global Select Market under the ticker symbol "CSRT." As of June 27, 2025, Cascade had an approximate market capitalization of $41.2 billion.
For its fiscal year ending January 31, 2025 ("FY2024"), Cascade reported total consolidated revenue of approximately $28.6 billion. Of this total, approximately $9.3 billion was derived from Cascade's e-commerce and marketplace revenue segment, which includes both direct-to-consumer e-commerce sales on CascadeDirect.com and marketplace services revenue from CascadeMarket. Cascade operates approximately 340 brick-and-mortar retail locations across 38 states, offering a broad range of consumer products including home goods, electronics, apparel, and general merchandise. Cascade also operates a direct-to-consumer e-commerce platform (CascadeDirect.com), through which it sells products directly to consumers as a first-party retailer.
In addition to its first-party retail operations, Cascade operates CascadeMarket, a third-party seller marketplace platform launched on June 1, 2019. CascadeMarket enables independent third-party sellers to list and sell products to consumers through Cascade's online platform, leveraging Cascade's existing consumer traffic, brand recognition, and fulfillment infrastructure. As of the end of FY2024, CascadeMarket had processed approximately $3.1 billion in GMV from approximately 42,000 active third-party sellers. CascadeMarket generated approximately $527 million in marketplace services revenue in FY2024, reflecting an approximate take rate of 17% (marketplace services revenue as a percentage of GMV). Marketplace services revenue includes commissions, referral fees, fulfillment and shipping fees, advertising fees, and payment processing fees charged to third-party sellers. Cascade operates a 22-warehouse nationwide fulfillment network that serves both its first-party e-commerce operations and CascadeMarket sellers who elect to use Cascade's fulfillment services ("Fulfilled by Cascade" or "FbC").
Pinnacle Market Group Inc. Pinnacle is a corporation organized and existing under the laws of the State of Delaware, with its principal executive offices located at 500 East 6th Street, Suite 800, Austin, Texas 78701. Pinnacle's common stock is listed and traded on the Nasdaq Global Select Market under the ticker symbol "PMGI." Prior to the public announcement of the merger, Pinnacle had an approximate market capitalization of $3.9 billion. Pinnacle was founded in 2014 by Rajiv Chandravar and Lena Kowalski, and completed its initial public offering on September 18, 2020.
For its fiscal year ending December 31, 2024 ("FY2024"), Pinnacle reported total GMV of approximately $11.4 billion, generated by approximately 185,000 active third-party sellers transacting through the Pinnacle platform. Pinnacle reported net revenue of approximately $1.82 billion in FY2024, reflecting an approximate take rate of 16% (net revenue as a percentage of GMV). Pinnacle's product categories include home goods, artisanal and handcrafted products, specialty foods, fashion and apparel, electronics and consumer technology, and health and beauty products. Pinnacle differentiates itself through its focus on curated, specialty, and artisanal products, its proprietary recommendation engine and product discovery algorithms, and its seller-support ecosystem, which includes marketing tools, analytics dashboards, and fulfillment partnerships.
C. The FTC's Challenge
On June 20, 2025, the FTC filed an administrative complaint (Docket No. 9438) challenging the proposed merger of Cascade and Pinnacle as a violation of Section 7 of the Clayton Act, 15 U.S.C. § 18, and Section 5 of the Federal Trade Commission Act, 15 U.S.C. § 45. Concurrently, on June 23, 2025, the FTC filed a complaint in the United States District Court for the Western District of Washington seeking a temporary restraining order and preliminary injunction under Section 13(b) of the FTC Act, 15 U.S.C. § 53(b), to preserve the status quo pending the outcome of the FTC's administrative proceeding. The Commission voted 3–2 to authorize the filing, with Commissioners Alderman and Sato dissenting.
The district court case has been assigned to the Honorable Richard A. Johannsen. Judge Johannsen entered a scheduling order on July 1, 2025, setting the evidentiary hearing on the FTC's motion for a preliminary injunction for September 8, 2025, with an estimated duration of five court days. Under the scheduling order, the FTC's opening brief and supporting declarations are due July 28, 2025; the defendants' opposition is due August 11, 2025; the FTC's reply is due August 22, 2025; and expert reports are due on a staggered schedule (FTC's expert report due August 4, 2025; defendants' expert report due August 18, 2025; rebuttal reports due August 29, 2025).
The FTC's litigation team is led by Claire Dunmore, Senior Trial Attorney, Bureau of Competition, Mergers IV Division, assisted by Samuel Ortega (Senior Trial Counsel) and Rebecca Yun (Staff Attorney). The Bureau of Economics staff economist assigned to the matter is Dr. Nathaniel Hargrove. The FTC has retained Dr. Wallace Keenan of Thornfield Research Group (1515 Wilson Boulevard, Suite 300, Arlington, Virginia 22209) as its testifying expert on market definition, competitive effects, and merger simulation. Dr. Keenan is a well-known industrial organization economist who has testified on behalf of the FTC and DOJ in a number of prior merger challenges, including FTC v. Staples Inc. (D.D.C. 2016) and FTC v. Wilhelmsen Maritime Services (D.D.C. 2018).
In addition to the FTC, the Independent Online Sellers Alliance ("IOSA"), a trade association representing approximately 12,000 independent online sellers, has filed a motion to intervene in the district court action on behalf of the FTC. IOSA is represented by Galloway & Peck LLP (Martina Galloway, lead counsel). IOSA's motion to intervene was filed on July 3, 2025, and is currently pending before Judge Johannsen. IOSA contends that its members — small and mid-sized sellers who operate on multiple marketplace platforms — will be directly and adversely affected by the proposed merger and that IOSA's perspective on the competitive effects of the merger will assist the Court.
III. THE FTC'S PROPOSED RELEVANT MARKET
A. Market as Alleged in the Complaint
The FTC's complaint alleges that the relevant product market for purposes of its Clayton Act Section 7 analysis is "online marketplace platform services for third-party sellers in the United States." Complaint ¶¶ 38–45. The FTC defines this market as encompassing the services provided by online platforms that connect independent third-party sellers with consumers in a two-sided marketplace model. Under the FTC's definition, the relevant product market includes the full bundle of services that marketplace platforms provide to sellers, including buyer aggregation and traffic generation, product search and discovery tools, payment processing and transaction infrastructure, review and trust systems (including buyer ratings and seller reputation mechanisms), and, in some cases, fulfillment and logistics services.
Critically, the FTC's proposed market definition excludes several significant categories of e-commerce activity. Specifically, the FTC excludes: (i) direct-to-consumer retail e-commerce, in which a retailer sells products that it owns and controls directly to consumers through the retailer's own website (e.g., CascadeDirect.com); (ii) brick-and-mortar retail, including the in-store sales operations of Cascade and other retailers with physical locations; (iii) social commerce platforms, such as integrated shopping features on social media platforms and social-commerce-first platforms like Brevity Social Commerce Inc.; and (iv) hybrid retail models in which a single platform operates both a first-party retail business and a third-party seller marketplace.
The FTC contends that sellers of marketplace platform services are not reasonably interchangeable with other e-commerce channels because marketplace platforms provide a distinct and integrated bundle of services that cannot be readily replicated by sellers operating through alternative channels. Specifically, the FTC argues that the buyer aggregation, product discovery, and trust infrastructure provided by established marketplace platforms represent a unique value proposition that sellers cannot feasibly replicate through their own websites, through social media channels, or through offline retail. The FTC further contends that the network effects inherent in marketplace platforms — whereby increased seller participation attracts more buyers, which in turn attracts more sellers — create a self-reinforcing dynamic that distinguishes marketplace platforms from other e-commerce channels and limits the substitutability of alternative channels.
B. FTC's Market Share Calculations
The FTC measures market shares in its proposed relevant market by GMV of U.S. online marketplace platform services. Based on these calculations, the FTC alleges the following market shares (Complaint ¶ 42):
The FTC derives these share figures from a combination of publicly available company disclosures, responses to the Second Request, third-party data from industry analytics firms, and estimates prepared by Dr. Keenan. The Complaint sources these figures at paragraph 42 and states that they are based on calendar year 2024 data. Of note, the FTC attributes to Cascade only its CascadeMarket GMV of $3.1 billion (yielding the 8.2% share) and does not include any of Cascade's direct-to-consumer e-commerce sales in the market share calculations. This selective attribution is, of course, a direct consequence of the FTC's artificially narrow market definition: by defining the market to include only "marketplace platform services for third-party sellers," the FTC is able to exclude Cascade's vastly larger first-party e-commerce business from the competitive calculus entirely.
C. FTC's HHI Analysis
The FTC presents the following HHI calculations in support of its claim that the proposed merger would substantially lessen competition in the alleged relevant market:
• Pre-merger HHI: 2,361 (Complaint ¶ 47)
• Post-merger HHI: 2,856 (Complaint ¶ 47)
• HHI Delta (change attributable to the merger): 495
The HHI delta is calculated as 2 × 8.2 × 30.1 = 493.64, which the FTC has rounded to 495 in its complaint presentation. Both the absolute level of the pre-merger HHI (above the 1,800 threshold used in the 2010 Horizontal Merger Guidelines, and above the 1,800 threshold identified in the 2023 Merger Guidelines as indicative of a "highly concentrated" market) and the delta (above the 200-point threshold that triggers a presumption of anticompetitive effects in highly concentrated markets) exceed the relevant thresholds set forth in the Horizontal Merger Guidelines. The FTC contends that these HHI figures create a structural presumption that the proposed merger is likely to substantially lessen competition, shifting the burden to the defendants to rebut the presumption with evidence of procompetitive efficiencies or other factors.
The pre-merger HHI of 2,361, which already exceeds the threshold for a highly concentrated market, reflects the existing concentration in the FTC's narrowly defined market. The FTC notes that the pre-merger market is dominated by two large players — Vertex Commerce at 35.7% and Pinnacle at 30.1% — with Nomad Shops at 14.6%, CascadeMarket at 8.2%, and a competitive fringe of smaller platforms collectively accounting for 11.4%. By combining Cascade and Pinnacle, the merger would create a firm with 38.3% of the market, making it the single largest player and nearly matching Vertex Commerce's 35.7% share. The FTC contends that this represents a significant increase in concentration in an already highly concentrated market.
D. FTC's Theory of Harm
The FTC's theory of competitive harm rests on several interrelated claims. First, the FTC alleges that the merger would combine two of the four significant online marketplace platforms in the United States, thereby eliminating head-to-head competition between Cascade's CascadeMarket and Pinnacle's marketplace platform. The FTC contends that CascadeMarket and Pinnacle currently compete for both sellers and buyers, and that this competition manifests in the form of competitive take rates, enhanced seller services and tools, platform innovation, and marketing efforts to attract both sellers and consumers. The merger would eliminate this competitive dynamic and reduce the incentive for the combined entity to compete aggressively.
Second, the FTC alleges that the post-merger combined firm would possess undue leverage over third-party sellers. Specifically, the FTC contends that the combined entity would have the ability and incentive to raise take rates charged to sellers, reduce the quality and scope of seller services (including fulfillment services, marketing tools, and analytics), and diminish the pace of platform innovation — all without losing a sufficient number of sellers to make such actions unprofitable. The FTC argues that this is because sellers who leave the combined platform would have limited alternatives, given that the post-merger market would be dominated by a "tight oligopoly" of two large platforms (the combined entity at 38.3% and Vertex Commerce at 35.7%), collectively accounting for approximately 74% of all marketplace GMV.
Third, the FTC alleges that the proposed merger would accelerate a "trend toward concentration" in the online marketplace platform industry. The FTC points to a series of acquisitions and organic consolidation events over the past several years and argues that the Cascade-Pinnacle merger represents the most significant consolidation event to date, one that would fundamentally and irreversibly alter the competitive landscape. The FTC contends that permitting this merger would further entrench the market positions of the remaining large platforms, raise barriers to entry for new competitors, and reduce the prospects for meaningful future competition.
Fourth, the FTC alleges that the post-merger market structure would facilitate coordinated effects. In a market with only two large platforms (the combined entity and Vertex Commerce) collectively controlling approximately 74% of marketplace GMV, the FTC contends that the conditions for tacit coordination or parallel accommodating conduct would be significantly enhanced. Specifically, the FTC argues that the post-merger duopoly would have the ability to observe and respond to each other's pricing and strategic decisions with sufficient speed and transparency to sustain supra-competitive take rates and reduced service quality over time, to the detriment of third-party sellers and, ultimately, consumers.
IV. CRITIQUE OF THE FTC'S MARKET DEFINITION
A. The FTC's Market Is Improperly Narrow — Analytical Framework
The foundational question in any merger challenge under Section 7 of the Clayton Act is the definition of the relevant market. Brown Shoe Co. v. United States, 370 U.S. 294, 324 (1962) ("The outer boundaries of a product market are determined by the reasonable interchangeability of use or the cross-elasticity of demand between the product itself and substitutes for it."). Market definition is not merely a preliminary step; it is the lens through which the entirety of the competitive analysis is conducted. An improperly narrow market definition will artificially inflate concentration statistics, create a false impression of market power, and distort the assessment of competitive effects. Conversely, a properly defined market will capture the full range of competitive constraints facing the merging parties and provide an accurate basis for evaluating the likely effects of the transaction.
Under established antitrust principles, the relevant product market must include all products or services that are reasonably interchangeable by consumers — or, in the context of a two-sided platform, by users on either side of the platform. Brown Shoe, 370 U.S. at 325; FTC v. Sysco Corp., 113 F. Supp. 3d 1, 24 (D.D.C. 2015) (noting that "the outer boundaries of a product market are determined by the reasonable interchangeability of use or the cross-elasticity of demand between the product itself and substitutes for it"). The Horizontal Merger Guidelines employ the hypothetical monopolist test — commonly referred to as the "SSNIP test" (Small but Significant Non-transitory Increase in Price) — as the principal analytical tool for delineating the relevant product market. Under the SSNIP test, the relevant market is defined as the smallest group of products such that a hypothetical monopolist controlling all products in the group could profitably impose a small but significant non-transitory increase in price (typically 5-10%) above competitive levels. If customers would respond to such a price increase by switching to products outside the candidate market in sufficient numbers to render the price increase unprofitable, then the candidate market is too narrow and must be expanded to include the substitute products.
Applied to the present case, the SSNIP test requires asking whether a hypothetical monopolist over "online marketplace platform services for third-party sellers" could profitably impose a small but significant increase in take rates — the effective "price" charged to sellers for marketplace services. If, in response to such a take-rate increase, a sufficient number of sellers would divert their sales volume to alternative channels — including direct-to-consumer e-commerce platforms, social commerce channels, aggregator platforms, or even offline retail — to render the take-rate increase unprofitable, then the FTC's proposed market is too narrow and must be expanded to include those alternative channels.
As set forth in detail below, the FTC's market definition fails the SSNIP test because it ignores the real-world substitution patterns of both sellers and consumers across multiple e-commerce channels. The evidence will demonstrate that sellers routinely multi-home across marketplace platforms and alternative e-commerce channels, that they shift sales volume in response to changes in take rates and service quality, and that consumer purchasing behavior spans the full spectrum of online retail channels. By confining the relevant market to "online marketplace platform services," the FTC has drawn an artificial boundary that excludes the very competitive constraints that discipline pricing and innovation in the e-commerce industry.
B. Demand-Side Substitution: Seller Perspective
The FTC's market definition rests on the premise that third-party sellers view marketplace platform services as a distinct product category that is not reasonably interchangeable with other e-commerce channels. This premise is flatly contradicted by the commercial realities of the e-commerce industry. Third-party sellers on marketplace platforms do not treat marketplace services as the sole or even primary channel for reaching consumers. Rather, the overwhelming majority of sellers simultaneously utilize multiple channels to distribute and sell their products, including:
(a) Direct-to-consumer websites. Many sellers operate their own proprietary e-commerce storefronts, built either on hosted platforms such as Dunmore Services Inc., Granite Harbor Services Inc., or Bramwell Health IT, or on custom-built websites. These storefronts enable sellers to reach consumers directly without intermediation by a marketplace platform, and to retain the full margin on each sale (less payment processing and marketing costs). The proliferation of turnkey e-commerce platform tools has dramatically reduced the cost and complexity of launching and operating a direct-to-consumer website, making this channel accessible even to small and mid-sized sellers.
(b) Social commerce platforms. An increasingly significant channel for online sellers is social commerce — the integration of shopping features directly into social media platforms and social-commerce-first platforms. Brevity Social Commerce Inc., launched in 2023, exemplifies this trend: it offers a social-commerce-first model that integrates many of the features traditionally associated with marketplace platforms (seller storefronts, buyer discovery tools, payment processing) within a social media environment. In addition, major social media platforms with massive user bases have integrated commerce features that enable sellers to list products, process transactions, and reach consumers directly within the social media environment.
(c) Direct-to-consumer aggregator platforms. A newer category of e-commerce channel is the direct-to-consumer aggregator, exemplified by Trove Marketplace Inc., which launched in 2024. These platforms aggregate multiple sellers' direct-to-consumer offerings into a unified shopping experience for consumers, offering many of the benefits of a marketplace (buyer aggregation, search and discovery) without the traditional marketplace intermediation model.
(d) Brick-and-mortar retail, wholesale, and consignment channels. Many sellers who operate on online marketplace platforms also sell through physical retail channels, including their own brick-and-mortar stores, wholesale relationships with retailers, pop-up shops, and consignment arrangements. While these channels are not "online," they represent a meaningful alternative for sellers seeking to reach consumers, and an increase in online marketplace take rates would likely cause some sellers to shift volume toward offline channels.
The prevalence of multi-homing among marketplace sellers is a critical fact that the FTC's market definition fails to account for. Multi-homing refers to the practice of sellers listing and selling their products through multiple platforms and channels simultaneously. The evidence will demonstrate that sellers on CascadeMarket, Pinnacle, Vertex Commerce, and Nomad Shops typically sell through multiple channels at the same time, dynamically allocating their inventory, marketing spend, and fulfillment resources across channels based on the relative cost, reach, and service quality of each channel. A take-rate increase on any single marketplace platform would cause seller diversion to these alternative channels — precisely the substitution response that the SSNIP test is designed to capture.
The cross-elasticity of demand between marketplace platform services and direct e-commerce retail channels is high. Sellers routinely shift volume between channels based on cost (take rates versus the cost of operating a direct website), buyer reach (marketplace traffic versus direct traffic), service quality (fulfillment, marketing tools, analytics), and strategic considerations (brand control, data ownership, customer relationship management). This fluidity of seller behavior across channels demonstrates that marketplace platform services and other e-commerce channels are reasonably interchangeable from the seller's perspective and therefore belong in the same relevant market.
Cascade's own internal data — which we should confirm with Brindoval Analytics during the forthcoming working session — likely demonstrates that CascadeMarket sellers derive only a fraction of their total sales from the CascadeMarket platform, with the remainder coming from direct websites, other marketplace platforms, social commerce channels, and offline channels. If, for example, the median CascadeMarket seller derives only 15-25% of its total sales revenue from CascadeMarket (a figure that is consistent with industry surveys and publicly available data on seller multi-homing behavior), this fact alone would powerfully undermine the FTC's contention that marketplace platform services constitute a distinct market. A seller that derives 75-85% of its revenue from non-marketplace channels is plainly not "locked in" to marketplace platforms in any meaningful sense.
C. Demand-Side Substitution: Consumer Perspective
The FTC's proposed market definition suffers from an additional, independently fatal deficiency: it focuses exclusively on the seller side of the marketplace platform and ignores the consumer side entirely. This analytical approach is not merely incomplete — it is affirmatively contrary to the framework established by the Supreme Court in Ohio v. Halcyon Corporation, 138 S. Ct. 2274 (2018), as discussed more fully in Section VI below. But even setting aside the Amex framework, the FTC's failure to account for consumer substitution patterns independently undermines its market definition.
Consumers do not limit their online shopping to marketplace platforms. The same consumer who purchases a handcrafted ceramic mug from a seller on Pinnacle's marketplace may also purchase a similar mug directly from the potter's own website, from a department store's e-commerce site, from a social media integrated shopping feature, or from a brick-and-mortar retail location. Consumer purchasing behavior is fluid across channels, driven by factors such as price, convenience, product selection, delivery speed, brand affinity, and the overall shopping experience. The FTC's proposed market definition, by focusing exclusively on the seller side of the platform, ignores this fundamental reality of consumer behavior.
The significance of consumer-side substitution for market definition purposes is straightforward. If a hypothetical monopolist of marketplace platform services were to raise take rates, and if sellers responded by passing those increased costs through to consumers in the form of higher prices on marketplace listings, consumers would have the option of purchasing the same or similar products through alternative channels — including the same seller's direct website, a competing retailer's website, or a brick-and-mortar store. This consumer diversion would reduce the volume of sales through the marketplace platform, making the take-rate increase unprofitable and confirming that the marketplace platform does not constitute a separate market.
The FTC's complaint defines the market exclusively from the seller's perspective — "online marketplace platform services for third-party sellers" — and treats the consumer side of the platform as analytically irrelevant. This is precisely the type of one-sided analysis that the Supreme Court rejected in Ohio v. Pinnacle Partners LLC. As discussed in Section VI below, marketplace platforms are quintessential two-sided transaction platforms in which sellers and buyers interact simultaneously, and the relevant market must account for competition on both sides of the platform.
Evidence that consumers freely substitute between purchasing from a marketplace listing and purchasing the same product directly from a seller's own website (or a competing retailer's site) demonstrates that marketplace platforms compete in the broader e-commerce retail market. Consumer surveys, browsing data, and purchase history data are all likely to confirm that consumers regularly compare prices and product availability across marketplace and non-marketplace channels before making purchasing decisions. This cross-channel comparison shopping behavior is the hallmark of demand-side substitutability and confirms that the FTC's narrow market definition is analytically unsound.
D. Supply-Side Substitution
In addition to the robust demand-side substitution discussed above, the FTC's market definition also fails to account for meaningful supply-side substitution. Supply-side substitution occurs when firms currently operating outside the candidate market can quickly and easily begin offering the products or services within the candidate market in response to a price increase, without incurring significant sunk costs. When supply-side substitution is sufficiently rapid and easy, the Merger Guidelines recognize that firms capable of such substitution should be included in the relevant market.
Numerous firms currently operating in adjacent e-commerce spaces can and do pivot to offer marketplace platform services with relative ease. The following examples illustrate the point:
Brevity Social Commerce Inc. Brevity is a Delaware corporation headquartered in Los Angeles, California. Launched in 2023, Brevity operates a social-commerce-first platform that integrates traditional marketplace features — including seller storefronts, buyer discovery tools, product search, and payment processing — within a social media environment. Brevity's rapid entry and expansion demonstrate that the technological and operational barriers to offering marketplace platform services are low. Brevity's business model also illustrates the blurring of boundaries between marketplace platforms and social commerce platforms, further undermining the FTC's attempt to draw a sharp line between "marketplace platform services" and other e-commerce channels.
Trove Marketplace Inc. Trove is a Delaware corporation headquartered in Chicago, Illinois. Launched in 2024, Trove initially operated as a direct-to-consumer aggregator platform, curating and presenting products from multiple independent sellers in a unified shopping experience. Since its launch, Trove has expanded its service offerings to include multi-seller marketplace functionalities, including seller-managed storefronts, competitive search and discovery tools, and integrated payment processing. Trove's trajectory — from direct-to-consumer aggregator to marketplace platform in less than one year — powerfully demonstrates the ease with which firms in adjacent e-commerce spaces can enter the marketplace platform segment.
Large direct-to-consumer retailers. Cascade itself provides perhaps the most compelling example of supply-side substitution in this case. Cascade launched CascadeMarket on June 1, 2019, leveraging its existing e-commerce infrastructure, consumer traffic, fulfillment network, and brand recognition to enter the marketplace platform segment. In under six years, CascadeMarket grew from zero to $3.1 billion in GMV and approximately 42,000 active third-party sellers. This organic entry by a large retailer with existing infrastructure demonstrates that the barriers to launching a marketplace platform are not prohibitive, and that new competitive entry can occur rapidly and at scale. Other large retailers with existing e-commerce operations and fulfillment infrastructure could similarly launch or expand marketplace platforms in response to supra-competitive take rates, further undermining the premise that "marketplace platform services" constitute a distinct market insulated from broader competitive forces.
Social media companies. Social media companies with massive existing user bases — in many cases numbering in the hundreds of millions of consumers in the United States alone — can and have integrated commerce features that create de facto marketplace platforms. These platforms possess the key ingredients that the FTC identifies as distinguishing marketplace platforms from other e-commerce channels: buyer aggregation, product discovery, social trust and review infrastructure, and payment processing. The ability of these platforms to enter or expand their marketplace offerings represents a significant supply-side competitive constraint that the FTC's market definition ignores.
The low barriers to entry in the marketplace platform segment are further evidenced by the FTC's own market share data. The FTC acknowledges that "All Others" — a category that includes Brevity Social Commerce Inc., Trove Marketplace Inc., and numerous smaller platforms — collectively account for 11.4% of GMV in the FTC's proposed market. The existence of this competitive fringe, composed of numerous platforms that have entered the market in recent years, confirms that the marketplace platform segment is characterized by relatively low barriers to entry and ongoing competitive entry. Yet the FTC draws the market boundary to exclude the far larger competitive constraints imposed by direct e-commerce channels, social commerce platforms, and offline retail — channels that collectively dwarf the marketplace platform segment in total GMV. This selective inclusion and exclusion of competitive constraints is the hallmark of a gerrymandered market definition.
E. Functional Interchangeability and Practical Indicia
Beyond the SSNIP test and the analysis of demand-side and supply-side substitution, courts have traditionally considered the "practical indicia" of market definition identified by the Supreme Court in Brown Shoe Co. v. United States, 370 U.S. 294, 325 (1962). These practical indicia include: (i) industry or public recognition of the market as a separate economic entity; (ii) the product's peculiar characteristics and uses; (iii) unique production facilities; (iv) distinct customers; (v) distinct prices; and (vi) sensitivity to price changes. Analysis of these practical indicia does not support the FTC's narrow market definition. To the contrary, each of the Brown Shoe factors points toward a broader market that encompasses all e-commerce retail or, at minimum, all online retail channels available to sellers.
Industry or public recognition. The e-commerce industry does not recognize "online marketplace platform services" as a separate and distinct industry or economic entity apart from e-commerce generally. Trade publications, industry analyst reports, and investment bank research consistently treat marketplace platforms as one channel within the broader e-commerce ecosystem. For example, analyst reports from Mercer Hollis & Co. and Ridgeline Capital Partners — both of which provided advisory services in connection with this transaction — analyze the competitive landscape in terms of the broader e-commerce retail market, not a standalone "marketplace platform services" market. Industry conferences and trade shows similarly treat marketplace platforms as one component of the larger e-commerce landscape. There is no separate SIC or NAICS code for "online marketplace platform services" distinct from e-commerce retail. The absence of industry recognition of the FTC's proposed market as a distinct economic entity is a significant indicator that the market is improperly drawn.
Peculiar characteristics and uses. The FTC contends that marketplace platforms have "peculiar characteristics" — buyer aggregation, search and discovery, payment processing, review and trust infrastructure, and fulfillment — that distinguish them from other e-commerce channels. But these characteristics are not peculiar to marketplace platforms. Direct-to-consumer e-commerce platforms aggregate buyer demand through their own marketing, search engine optimization, and brand recognition. Social commerce platforms aggregate buyer audiences through social media reach and engagement. Payment processing is universally available through third-party processors (e.g., Kestrel Group, Ashford Corporation, Beaumont Corporation). Review and trust infrastructure is provided by independent third-party review platforms (e.g., Beaumont Corporation, Pinnacle Partners LLC). Fulfillment services are offered by independent third-party logistics providers (e.g., Adriatic & Co., Severin Partners LLC). None of the characteristics identified by the FTC is unique to marketplace platforms; all are available through alternative channels or through third-party service providers. This lack of peculiar characteristics weighs against treating marketplace platforms as a separate market.
Unique production facilities. Marketplace platforms do not require unique production facilities that are unavailable to operators of other e-commerce channels. The technology stack required to operate a marketplace platform — web hosting, database management, search algorithms, payment processing integration, and user interface design — is widely available and is used by direct e-commerce platforms, social commerce platforms, and aggregator platforms alike. The fulfillment infrastructure used by marketplace platforms (warehouses, shipping logistics) is the same infrastructure used by direct-to-consumer retailers. There is no unique production facility or proprietary technology that confines marketplace platforms to a separate market.
Distinct customers. The FTC's market definition implicitly assumes that sellers using marketplace platforms are "distinct customers" who are confined to marketplace platforms and do not have access to alternative channels. As discussed above in Section IV.B, this assumption is contradicted by the pervasive multi-homing behavior of marketplace sellers, who simultaneously sell through multiple marketplace platforms, direct-to-consumer websites, social commerce channels, and offline channels. Similarly, on the consumer side, marketplace platform consumers are the same consumers who shop on brand websites, department store e-commerce sites, social media commerce features, and brick-and-mortar stores. Neither sellers nor consumers on marketplace platforms constitute a "distinct" customer base confined to marketplace platforms.
Distinct prices. Marketplace platform take rates — the effective "price" of marketplace services — range from approximately 15% to 20% across the major platforms. But these take rates are not "distinct" prices for a distinct product; rather, they reflect the cost of a particular bundle of services (buyer aggregation, payment processing, fulfillment, marketing) that sellers can obtain through alternative means. The effective cost of reaching consumers through a direct-to-consumer website (including marketing, payment processing, and fulfillment costs) may be comparable to, or even higher or lower than, the take rate charged by a marketplace platform, depending on the seller's specific circumstances. The fact that take rates are expressed as a percentage of GMV rather than as a flat fee does not make them "distinct" in any economically meaningful sense; it merely reflects the pricing convention of the marketplace platform business model.
Sensitivity to price changes. As discussed in Section IV.B, sellers are highly sensitive to changes in marketplace take rates and respond to take-rate increases by shifting volume to alternative channels. This cross-elasticity of demand between marketplace platform services and alternative e-commerce channels is strong evidence that marketplace platforms and other e-commerce channels are in the same relevant market. If marketplace take rates were not constrained by competition from alternative channels, one would expect to see take rates significantly higher than the 15-20% range currently observed — a range that is consistent with competitive pricing for the bundle of services provided, not with the exercise of market power in a narrowly defined market.
In sum, none of the Brown Shoe practical indicia supports the FTC's proposed narrow market definition. To the contrary, each factor points toward a broader market that includes all e-commerce retail channels.
V. THE CORRECT MARKET DEFINITION: ALL E-COMMERCE RETAIL
A. Proposed Market: "All E-Commerce Retail in the United States"
For the reasons set forth in Section IV, the relevant product market should be defined to encompass all e-commerce retail channels through which sellers can reach consumers and consumers can purchase goods online in the United States. This market definition accurately reflects the competitive realities of the e-commerce industry, in which sellers and consumers routinely substitute across multiple channels, and in which the services offered by marketplace platforms are functionally interchangeable with those offered by other e-commerce channels.
Under defendants' proposed market definition, the relevant market includes the following categories of e-commerce activity:
(a) Third-party seller marketplace platforms — platforms that connect independent third-party sellers with consumers in a two-sided marketplace model (e.g., CascadeMarket, Pinnacle, Vertex Commerce, Nomad Shops, Brevity Social Commerce, Trove Marketplace);
(b) First-party direct retail e-commerce — online retail operations in which a retailer sells products that it owns and controls directly to consumers through the retailer's own website or app (e.g., CascadeDirect.com, major department store e-commerce sites, specialty retailer websites);
(c) Hybrid models — retailers that operate both a first-party direct retail e-commerce business and a third-party seller marketplace on the same platform (e.g., Cascade, which operates both CascadeDirect.com and CascadeMarket);
(d) Social commerce platforms — platforms that integrate shopping features directly into a social media environment, enabling sellers to list products, process transactions, and reach consumers within the social media context (e.g., Brevity Social Commerce, integrated shopping features on major social media platforms);
(e) Direct-to-consumer brand websites — independent e-commerce websites operated by individual brands or sellers, often built on hosted platforms such as Dunmore Services Inc., Granite Harbor Services Inc., or Bramwell Health IT; and
(f) Aggregator platforms — platforms that aggregate product listings from multiple sellers into a unified shopping experience without operating a traditional marketplace intermediation model (e.g., Trove Marketplace, price comparison sites, product search engines).
This market definition is consistent with the analytical framework of the Horizontal Merger Guidelines, which instructs that the relevant market should be the smallest group of products such that a hypothetical monopolist could profitably impose a SSNIP. As demonstrated in Section IV, a hypothetical monopolist of "online marketplace platform services" alone could not profitably raise take rates because sellers and consumers would divert to the alternative channels enumerated above. The market must therefore be expanded to include all e-commerce retail channels.
B. Market Size and Shares Under the Broader Definition
Total U.S. e-commerce GMV in 2024 was approximately $757 billion, based on widely cited industry estimates from the U.S. Census Bureau's Annual Retail Trade Survey, industry analytics firms, and publicly available company disclosures. This figure encompasses all online retail sales by U.S. consumers, including sales through marketplace platforms, first-party retailer websites, social commerce platforms, direct-to-consumer brand websites, and aggregator platforms.
Under the "all e-commerce retail" market definition, the combined entity's market share can be calculated in two ways, depending on whether Cascade's direct-to-consumer e-commerce sales are included:
Marketplace GMV only. The combined marketplace GMV of CascadeMarket ($3.1 billion) and Pinnacle ($11.4 billion) is $14.5 billion. As a share of total U.S. e-commerce GMV: $14.5 billion / $757 billion = approximately 1.9%. This figure captures only the marketplace transaction volumes of the merging parties and excludes Cascade's vastly larger first-party e-commerce business.
Total e-commerce GMV (marketplace + direct). Cascade's e-commerce and marketplace segment revenue of $9.3 billion, when adjusted for Cascade's blended take rate and product margins, corresponds to an estimated total e-commerce GMV of approximately $43.7 billion (including both first-party direct sales and CascadeMarket GMV). Combined with Pinnacle's marketplace GMV of $11.4 billion, the combined entity's total e-commerce GMV would be approximately $55.1 billion. As a share of total U.S. e-commerce GMV: $55.1 billion / $757 billion = approximately 7.3%.
Even under the more generous calculation that includes Cascade's entire e-commerce footprint, the combined entity's share of all U.S. e-commerce retail is approximately 7.3%. This share is far below the 30% threshold at which courts typically begin to find that a firm possesses meaningful market power. See, e.g., United States v. Fenmore Industries, 415 U.S. 486, 494–96 (1974) (noting that market shares are relevant indicators of competitive significance but must be assessed in context); FTC v. Arch Coal, Inc., 329 F. Supp. 2d 109, 129 (D.D.C. 2004) (requiring the FTC to show that the combined firm would have a sufficiently large market share to raise competitive concerns). A combined share of 7.3% — or 1.9% measured by marketplace GMV alone — is plainly insufficient to support an inference of market power or a structural presumption of illegality.
The HHI under the broader market definition is correspondingly benign. Given the highly fragmented nature of the total U.S. e-commerce market — in which no single firm accounts for more than approximately 37-40% of total GMV, and numerous mid-sized and smaller participants compete vigorously — the post-merger HHI under the broader market would remain well below the 1,500 threshold for "moderately concentrated" markets under the Merger Guidelines, let alone the 2,500 threshold for "highly concentrated" markets. The HHI delta attributable to the merger under the broader market definition would be negligible and well below the 100-point or 200-point thresholds that trigger further scrutiny or a presumption of anticompetitive effects.
C. Alternative Narrower Markets That Still Defeat the FTC's Theory
Even if the Court is not persuaded that "all e-commerce retail" is the appropriate relevant market, several intermediate market definitions — broader than the FTC's proposed market but narrower than "all e-commerce retail" — would still substantially reduce the combined entity's apparent market share to levels that do not support a presumption of illegality. These alternative market definitions include:
(a) "Online retail channels available to third-party sellers." This market would include all channels through which independent third-party sellers can reach consumers online, including marketplace platforms, direct-to-consumer e-commerce storefronts (e.g., Dunmore Services Inc.-based websites), social commerce platforms, and aggregator platforms. This definition excludes first-party retail e-commerce but includes all channels that compete for the same sellers who use marketplace platforms. Under this definition, the combined entity's market share would be significantly diluted by the inclusion of the enormous volume of direct-to-consumer e-commerce sales by third-party sellers.
(b) "Multi-channel e-commerce." This market would encompass all e-commerce channels through which multi-homing sellers reach consumers, defined by the actual behavior of sellers who use multiple channels simultaneously. Under this definition, the relevant market would include the full range of channels used by the seller population that currently transacts on marketplace platforms, reflecting the real-world competitive alternatives available to those sellers.
Under any of these broader-but-still-narrower-than-all-e-commerce definitions, the combined entity's market share remains well below levels that would support a structural presumption of illegality. The exact market share under each alternative definition will depend on the empirical analysis to be conducted by Brindoval Analytics, but preliminary estimates suggest that the combined share under any of these intermediate definitions would be in the range of 5-15% — far below the threshold for competitive concern.
The presentation of alternative market definitions is strategically important. Even if the Court is inclined to reject the broadest "all e-commerce retail" definition, the availability of multiple intermediate market definitions — all of which yield combined shares well below presumption thresholds — provides the Court with a range of analytically defensible options, any one of which would be fatal to the FTC's case. The FTC's narrow market is an outlier that produces inflated concentration statistics; every other plausible market definition yields benign concentration levels.
VI. THE FTC'S MARKET DEFINITION FAILS UNDER OHIO V. Pinnacle Partners LLC
A. Two-Sided Platform Analysis
In Ohio v. Halcyon Corporation, 138 S. Ct. 2274 (2018), the Supreme Court addressed the question of how antitrust analysis should be applied to two-sided transaction platforms. The Court held that for two-sided transaction platforms — platforms that "facilitate a single, simultaneous transaction between participants" on both sides — the relevant market must encompass both sides of the platform because "the two sides are interlinked" and "changes on one side of the platform" necessarily "affect[] the other side." Id. at 2286. The Court distinguished two-sided transaction platforms from two-sided non-transaction platforms (such as newspapers, which sell advertising to advertisers and content to readers, but do not facilitate a direct transaction between the two groups), holding that the former require a unified market analysis that considers competition on both sides simultaneously.
The Court's reasoning rested on the fundamental economic insight that in a two-sided transaction platform, the "price" charged to one side of the platform cannot be evaluated in isolation from the "price" and value delivered to the other side. An increase in the price charged to one side (e.g., merchants) may be offset by a decrease in the price charged to, or an increase in the value delivered to, the other side (e.g., cardholders), with the net competitive effect being ambiguous or even procompetitive. Evaluating the competitive effects of a practice on only one side of the platform therefore risks condemning conduct that is in fact procompetitive when both sides are considered, or overlooking anticompetitive effects that manifest on the other side.
Online marketplace platforms are quintessential two-sided transaction platforms within the meaning of Amex. They facilitate simultaneous transactions between sellers and buyers: when a consumer purchases a product from a seller on CascadeMarket or Pinnacle, a single, integrated transaction occurs on the platform between the seller (who provides the product) and the buyer (who provides the payment). The platform's role is to facilitate this transaction by providing the infrastructure, trust mechanisms, and matching services that enable it to occur. The platform charges the seller a take rate (the "price" on the seller side) and provides the buyer with product selection, search and discovery, trust and review infrastructure, and a convenient shopping experience (the "value" on the buyer side, often at no explicit monetary price). These two sides are inextricably linked: an increase in take rates affects seller participation, which in turn affects consumer choice and the consumer value proposition, which feeds back to seller value through reduced buyer traffic and conversion rates.
The FTC's complaint defines the market exclusively from the seller's perspective — "online marketplace platform services for third-party sellers" — and ignores the consumer side entirely. This one-sided approach is precisely the analytical error that the Supreme Court rejected in Amex. By focusing only on the seller side, the FTC can characterize the competitive landscape in terms of the take rates and services offered to sellers, while ignoring the intense competition for consumer attention and spending that occurs across all e-commerce channels. This selective framing produces a distorted picture of the competitive dynamics in the e-commerce industry.
B. Implications for Market Definition
If the Court applies the Amex framewo