nep-com New Economics Papers
on Industrial Competition
Issue of 2025–08–18
thirteen papers chosen by
Russell Pittman, United States Department of Justice


  1. A Novel Argument on Regulating Prices in Two-sided Markets: Finding Win-Win Policy Correctly By Yukihiro Nishimura
  2. Stability of multiple cartels in differentiated markets By Khan, Abhimanyu; Peeters, Ronald
  3. Designing Vertical Differentiation with Information By Christoph Carnehl; Anton Sobolev; Konrad Stahl; André Stenzel; Konrad O. Stahl
  4. Markups, Markdowns, and Bargaining in a Vertical Supply Chain By Rémi Avignon; Claire Chambolle; Etienne Guigue; Hugo Molina
  5. Public Communication and Collusion: New Screening Tools for Competition Authorities By Tomaso Duso; Joseph E., Jr. Harrington; Carl Kreuzberg; Geza Sapi
  6. Concentration and Markups in International Trade By Alviarez Vanessa; Fioretti Michele; Kikkawa Ken; Morlacco Monica
  7. Algorithmic Coercion with Faster Pricing By Zach Y. Brown; Alexander MacKay
  8. AI-Powered Trading, Algorithmic Collusion, and Price Efficiency By Winston Wei Dou; Itay Goldstein; Yan Ji
  9. Comparing the effects of subsidies on target goods By Dertwinkel-Kalt, Markus; Wey, Christian
  10. Digital Media Mergers: Theory and Application to Facebook-Instagram By Justin Katz; Hunt Allcott
  11. Trial Length, Pricing, and Rationally Inattentive Customers By F. Nguyen
  12. Banking market consolidation in Asia: Evidence from acquirers, targets, and rivals By Kolaric, Sascha; Kiesel, Florian; Schiereck, Dirk
  13. Measuring Markets for Network Goods By Leonardo Bursztyn; Matthew Gentzkow; Rafael Jimenez-Duran; Aaron Leonard; Filip Milojevic; Christopher Roth; Matthew Gentzkow

  1. By: Yukihiro Nishimura (Osaka University and CESifo)
    Abstract: Online markets like app stores are typically characterized by a monopoly who set prices on both sides — the prices of the network good (such as iPhone) and the commission fee to participating firms. There is an ongoing concerns on the welfare consequences of imperfect competition, where the antitrust authorities in the EU are keen about the monopolistic commission fee. With online apps as a representative example, this study investigates the welfare effects of price ceiling policies. The following results are shown. If the network-size externality on apps’ price is stronger than the app variety’s network externality, then, first, the price ceiling on the network good increases both the producer surplus of the app developers and the consumer surplus of the end-users. Second, in contrast, the price ceiling on the commission fee for the developers reduces the consumer surplus. The reverse proposition holds when the order of the strength of two network externalities is reversed. By the level of the unconstrained equilibrium commission fee, a regulator can identify which policy would make both consumers and developers better off.
    Keywords: Digital economy; Platform; Antitrust pricing; Network externality
    JEL: F23 L13 D85 K21 L86
    Date: 2025–07
    URL: https://d.repec.org/n?u=RePEc:osk:wpaper:2505
  2. By: Khan, Abhimanyu; Peeters, Ronald
    Abstract: We characterize stable market structures under price-competition in differentiated markets when multiple cartels may form. Market structures without cartelisation are never stable and always involve multiple small cartels, and, but for one knife-edge case, only involves multiple small cartels. Combined with the result that the unique stable market structure under quantity-competition is also characterised by multiple small cartels, this underscores the importance of considering the possibility of multiple cartels in competition policy. Comparing stable market structures under price and quantity competition, we find that prices and profits are higher under price-competition whenever the market is sufficiently differentiated or sufficiently concentrated.
    Keywords: multiple cartels; stable cartels; price competition; differentiated markets
    JEL: C70 D43 L13
    Date: 2025–07–03
    URL: https://d.repec.org/n?u=RePEc:pra:mprapa:125199
  3. By: Christoph Carnehl; Anton Sobolev; Konrad Stahl; André Stenzel; Konrad O. Stahl
    Abstract: We study information design in a vertically differentiated market. Two firms offer products of ex-ante unknown qualities. A third party designs a system to publicly disclose information. More precise information guides consumers toward their preferred product but increases expected product differentiation, allowing firms to raise prices. Full disclosure of the product ranking alone suffices to maximize industry profits. Consumer surplus is maximized, however, whenever no information about the product ranking is disclosed, as the benefit of competitive pricing always dominates the loss from suboptimal choices. The provision of public information on product quality becomes questionable.
    Keywords: information design, vertical product differentiation, quality rankings, competition
    JEL: D43 D82 L13 L15
    Date: 2025
    URL: https://d.repec.org/n?u=RePEc:ces:ceswps:_12038
  4. By: Rémi Avignon; Claire Chambolle; Etienne Guigue; Hugo Molina
    Abstract: This article bridges monopoly, monopsony, and countervailing power theories to analyze their welfare implications in a vertical supply chain. We develop a bilateral monopoly model with bargaining that accommodates upstream monopsony and downstream monopoly power. In equilibrium, the ‘‘short-side rule'' applies: the quantity exchanged is determined by the firm willing to trade less. Welfare is maximized when each firm's bargaining power exactly countervails the other's market power. Otherwise, double marginalization arises in the form of double markdownization under excessive downstream bargaining power, or double markupization under excessive upstream bargaining power. We offer novel insights for price regulation and competition policy.
    Keywords: markups, markdowns, bargaining, countervailing buyer power, monopsony power, bilateral monopoly
    JEL: C78 D42 J42
    Date: 2025
    URL: https://d.repec.org/n?u=RePEc:ces:ceswps:_12026
  5. By: Tomaso Duso; Joseph E., Jr. Harrington; Carl Kreuzberg; Geza Sapi
    Abstract: Competition authorities increasingly rely on economic screening tools to identify markets where firms deviate from competitive norms. Traditional screening methods assume that collusion occurs through secret agreements. However, recent research highlights that firms can use public announcements to coordinate decisions, reducing competition while avoiding detection. We propose a novel approach to screening for collusion in public corporate statements. Using natural language processing, we analyze more than 300, 000 earnings call transcripts issued worldwide between 2004 and 2022. By identifying expressions commonly associated with collusion, our method provides competition authorities with a tool to detect potentially anticompetitive behavior in public communications. Our approach can extend beyond earnings calls to other sources, such as news articles, trade press, and industry reports. Our method informed the European Commission’s 2024 unannounced inspections in the car tire sector, prompted by concerns over price coordination through public communication.
    Keywords: communication, collusion, NLP, screening, text analysis
    JEL: C23 D22 L1 L4 L64
    Date: 2025
    URL: https://d.repec.org/n?u=RePEc:ces:ceswps:_12029
  6. By: Alviarez Vanessa; Fioretti Michele; Kikkawa Ken; Morlacco Monica
    Abstract: This paper derives a closed-form expression linking aggregate markups on imported inputs to concentration in a model of firm-to-firm trade with two-sided market power. Our theory extends standard oligopoly insights in two dimensions. First, it reveals that markups increase with exporter concentration and decrease with importer concentration, reflecting the balance of oligopoly and oligopsony forces. Second, it adapts conventional market definitions to reflect rigid trading relationships, yielding new concentration measures that capture competition in firm-to-firm trade. Analysis of Colombian transaction-level import data shows these differences are key to understanding markup dynamics in international trade.
    Date: 2025–08
    URL: https://d.repec.org/n?u=RePEc:arx:papers:2508.00345
  7. By: Zach Y. Brown; Alexander MacKay
    Abstract: We examine a model in which one firm uses a pricing algorithm that enables faster pricing and multi-period commitment. We characterize a coercive equilibrium in which the algorithmic firm maximizes its profits subject to the incentive compatibility constraint of its rival. By adopting an algorithm that enables faster pricing and (imperfect) commitment, a firm can unilaterally induce substantially higher equilibrium prices even when its rival maximizes short-run profits and cannot collude. The algorithmic firm can earn profits that exceed its share of collusive profits, and coercive equilibrium outcomes can be worse for consumers than collusive outcomes. In extensions, we incorporate simple learning by the rival, and we explore the implications for platform design.
    JEL: D43 L13 L40 L81 L86
    Date: 2025–07
    URL: https://d.repec.org/n?u=RePEc:nbr:nberwo:34070
  8. By: Winston Wei Dou; Itay Goldstein; Yan Ji
    Abstract: The integration of algorithmic trading with reinforcement learning, termed AI-powered trading, is transforming financial markets. Alongside the benefits, it raises concerns for collusion. This study first develops a model to explore the possibility of collusion among informed speculators in a theoretical environment. We then conduct simulation experiments, replacing the speculators in the model with informed AI speculators who trade based on reinforcement-learning algorithms. We show that they autonomously sustain collusive supra-competitive profits without agreement, communication, or intent. Such collusion undermines competition and market efficiency. We demonstrate that two separate mechanisms are underlying this collusion and characterize when each one arises.
    JEL: D43 G10 G14 L13
    Date: 2025–07
    URL: https://d.repec.org/n?u=RePEc:nbr:nberwo:34054
  9. By: Dertwinkel-Kalt, Markus; Wey, Christian
    Abstract: We analyze the equilibrium effects of different subsidies on target goods under both perfectly competitive and monopolistic market structures. We concentrate our analysis on three particularly common forms of subsidies: (i) a per-unit subsidy, (ii) an ad valorem subsidy, and (iii) an "inversely related" subsidy, which increases as the price of the target good decreases. To evaluate the price effects of the subsidies, we rely on two criteria, an "equal-relief" criterion-which relies on a pass-through analysis-and a cost-effectiveness criterion. Overall, the ad valorem subsidy always yields the strongest price-increasing effect, whereas an inversely related subsidy leads to the lowest price increase. Consequently, the ad valorem subsidy induces the largest output expansion under perfect competition, whereas the inversely related subsidy dominates the other subsidies in a monopoly under both criteria. Those findings are consistent with several empirical facts, such as observed price differences for green target goods across European countries.
    Keywords: Subsidies, Target Goods, Equal-relief, Pass Through, Cost Effectiveness
    JEL: D04 D40 H20
    Date: 2025
    URL: https://d.repec.org/n?u=RePEc:zbw:dicedp:323232
  10. By: Justin Katz; Hunt Allcott
    Abstract: We present a new model of competition between digital media platforms with targeted advertising. The model adds new insights around how user heterogeneity and overlap, along with user and advertiser substitution patterns, determine equilibrium ad load. We apply the model to evaluate the proposed separation of Facebook and Instagram. We estimate structural parameters using evidence on diminishing returns to advertising from a new randomized experiment and information on user overlap, diversion ratios, and price elasticity from earlier experiments. In counterfactual simulations, a Facebook-Instagram separation increases ad loads, transferring surplus from platforms and users to advertisers, with limited total surplus effects.
    JEL: D12 L1 L4 L86
    Date: 2025–07
    URL: https://d.repec.org/n?u=RePEc:nbr:nberwo:34028
  11. By: F. Nguyen
    Abstract: The "free trial" followed by automatic renewal is a dominant business model in the digital economy. Standard models explain trials as a mechanism for consumers to learn their valuation for a product. We propose a complementary theory based on the rational inattention framework. Consumers know their valuation but face a cognitive cost to remember to cancel an unwanted subscription. We model this using a Shannon entropy-based cost of information processing, where a consumer's baseline attention level decays with the length of the trial period. This creates a novel trade-off for a monopolist firm: a longer trial increases "inattentive revenue" from consumers who fail to cancel, but it also lowers ex-ante consumer utility, making the initial offer less attractive. We show that this trade-off leads to an interior optimal trial length, even for products where value-learning is instantaneous. Our model, under standard assumptions about demand elasticity and the distribution of consumer valuations, generates sharp, testable predictions about the relationship between contract terms. We find that the optimal renewal price and trial length are complements: firms offering longer trials will also set higher post-trial prices. We analyze the impact of policies aimed at curbing consumer exploitation, such as "click-to-cancel" regulations. We show that such policies, by making attention effectively cheaper, lead firms to reduce trial lengths. The effect on price depends directly on the elasticity of demand from loyal subscribers. We also extend the model to include paid trials, showing that introductory prices and trial lengths act as strategic substitutes. Our framework provides a micro-founded explanation for common features of subscription contracts and offers a new lens through which to evaluate consumer protection policies in digital markets.
    Date: 2025–07
    URL: https://d.repec.org/n?u=RePEc:arx:papers:2507.06422
  12. By: Kolaric, Sascha; Kiesel, Florian; Schiereck, Dirk
    Abstract: We analyse the financial sector consolidation in Asia by using a comprehensive sample of bank M&As from 1995 to 2021. Our results show that M&A announcements by Asian domestic acquirers are associated with significant positive stock price returns to both acquirers and their rivals. In contrast, cross‐border acquirers and their rivals experience negative but insignificant returns, while targets and their rivals record gains, regardless whether it is a domestic or cross‐border transaction. Further analyses reveal that domestic acquirers obtaining larger relative increases in their market share benefit the most, indicating that market power considerations are the primary driver behind acquirers' positive returns. For cross‐border acquirers, neither cultural differences nor regulatory arbitrage considerations can explain return patterns surrounding M&A announcements.
    Date: 2025–07–30
    URL: https://d.repec.org/n?u=RePEc:dar:wpaper:156087
  13. By: Leonardo Bursztyn; Matthew Gentzkow; Rafael Jimenez-Duran; Aaron Leonard; Filip Milojevic; Christopher Roth; Matthew Gentzkow
    Abstract: Market definition is essential for antitrust analysis, but challenging in settings with network effects, where substitution patterns depend on changes in network size. To address this challenge, we conduct an incentivized experiment to measure substitution patterns for TikTok, a popular social media platform. Our experiment, conducted during a time of high uncertainty about a potential U.S. TikTok ban, compares changes in the valuation of other social apps under individual and collective TikTok deactivations. Consistent with a simple framework, the valuations of alternative social apps increase more in response to a collective TikTok ban than to an individual TikTok deactivation. Our framework and estimates highlight that individual and collective treatments can even lead to qualitatively different conclusions about which alternative goods are substitutes.
    Keywords: markets, network goods, coordination, collective interventions
    JEL: D83 D91 P16 J15
    Date: 2025
    URL: https://d.repec.org/n?u=RePEc:ces:ceswps:_12049

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