About

Juan Ortner is a Professor in the Department of Economics at Boston University, located at 270 Bay State Road, Boston, MA 02215. His research interests encompass microeconomic theory, game theory, industrial organization, and political economy. His work involves analyzing strategic interactions in markets, auctions, and political settings, with a focus on collusion, security issuance, privacy, and bargaining. Ortner has contributed to the understanding of cartel behavior, auction design, and regulatory mechanisms through various theoretical models and empirical approaches. His publications include influential articles in leading economic journals such as the American Economic Review, Econometrica, the Journal of Political Economy, and Theoretical Economics, among others. His research often explores the design of algorithms and mechanisms to detect and prevent collusion, the role of privacy and information in market outcomes, and the dynamics of bargaining and political gridlock.

Research topics

• Computer Science
• Industrial organization
• Econometrics
• Marketing
• Computer Security
• Microeconomics
• Economics
• Business
• Internet privacy
• Mathematics
• Statistics

Selected publications

• The Equilibrium Design of a Third-Party's Pricing Algorithm

  SSRN Electronic Journal · 2025-01-01

  preprintOpen accessSenior author
  PublisherDOI

• Markets for Models

  2025-07-02

  articleOpen access

  Prediction problems are ubiquitous in the economy. To give a few examples, firms selling products often want to predict customers' willingness to pay and may use business analytics tools to do so. In science and engineering, researchers want to predict the viability of compounds in domains ranging from drug discovery to materials science. Campaigns and observers want to predict elections, and may commission polls to do so.

  PublisherOA PDFDOI

• The Value of Privacy in Cartels: An Analysis of the Inner Workings of a Bidding Ring

  The Review of Economic Studies · 2025-04-12 · 4 citations

  articleOpen accessSenior author

  Abstract We study how incentive constraints can be relaxed by randomization in a repeated-game setting. Our study is motivated by the workings of a detected bidding cartel that adopted a protocol of keeping the winning bid secret from the designated losers when defection was a concern. Keeping the winning bid secret makes accurately undercutting the winning bid more difficult and makes defection less attractive as potential defectors risk not winning the auction even if they deviate. We formalize these ideas in the context of a repeated-game setting and show that a cartel can attain higher payoffs by having the pre-selected winner randomize its bid and keep it secret from other members. Calibration of the model to the bid data of the cartel suggests that randomization may increase firms’ profits by about 56%.

  PublisherOA PDFDOI

• Markets for Models

  ArXiv.org · 2025-03-04

  preprintOpen access

  Motivated by the prevalence of prediction problems in the economy, we study markets in which firms sell models to a consumer to help improve their prediction. Firms decide whether to enter, choose models to train on their data, and set prices. The consumer can purchase multiple models and use a weighted average of the models bought. Market outcomes can be expressed in terms of the \emph{bias-variance decompositions} of the models that firms sell. We give conditions when symmetric firms will choose different modeling techniques, e.g., each using only a subset of available covariates. We also show firms can choose inefficiently biased models or inefficiently costly models to deter entry by competitors.

  PublisherOA PDFDOI

• Scoring and Cartel Discipline in Procurement Auctions

  SSRN Electronic Journal · 2025-01-01

  articleOpen access
  PublisherDOI

• Scoring and Cartel Discipline in Procurement Auctions

  National Bureau of Economic Research · 2025-04-01

  reportOpen access1st authorCorresponding

  Auctioneers suspecting bidder collusion often lack the formal evidence needed for legal recourse.A practical alternative is to design auctions that hinder collusion.Since Abreu et al. (1986), economic theory has emphasized imperfect monitoring as a constraint on collusion, but evidence remains scarce on whether: (i) information frictions meaningfully limit real-world collusion; and (ii) auctioneers can effectively exploit these frictions.Indeed, transparency concerns often prevent the introduction of explicit randomness in auction design.We make progress on this issue by studying the impact of subjective scoring in auctions run by Japan's Ministry of Land, Infrastructure, and Transportation.The adoption of scoring auctions significantly reduced winning bids in ways inconsistent with competition.Model-based inference suggests that the cartel's dynamic obedience constraints were binding and were tightened by imperfect monitoring.Subjective scoring can successfully leverage imperfect monitoring frictions to reduce the scope of collusion.

  PublisherDOI

• Regulating Collusion

  CrimRxiv · 2023-10-03

  articleOpen accessSenior author
  PublisherOA PDFDOI

• Regulating Collusion

  Annual Review of Economics · 2023-03-27 · 13 citations

  articleOpen accessSenior author

  We attempt to provide a systemic view of the process of regulating collusion, including detection and prosecution as well as bargaining between firms and regulators via consent orders, the production of evidence, and containment measures that may be taken if collusion cannot be addressed with more direct means. In addition, we try to do justice to the peculiarities of the legal system: Modeling the courts as they are, rather than as economists think they should be, is essential for economic analysis to improve the way collusion is regulated.

  PublisherOA PDFDOI

• Bargaining with evolving private information

  Theoretical Economics · 2023-01-01 · 5 citations

  articleOpen access1st authorCorresponding

  I study how the arrival of new private information affects bargaining outcomes. A seller makes offers to a buyer. The buyer is privately informed about her valuation and the seller privately observes her stochastically changing cost of delivering the good. Prices fall gradually at the early stages of negotiations, and trade is inefficiently delayed. The first‐best is implementable via a mechanism, whereas all equilibrium outcomes of the bargaining game are inefficient.

  PublisherDOI

• Mediated Collusion

  Journal of Political Economy · 2023-09-06 · 5 citations

  article1st authorCorresponding

  Cartels and bidding rings are often facilitated by intermediaries, who recommend prices/bids to firms and can impose penalties (such as reverting to competitive behavior in future interactions) if these recommendations are not followed. Motivated by such cases, we study correlated equilibria in first-price procurement auctions with complete information, where bidders who disobey their recommendations are penalized. Cartel-optimal profit is greater when more information about submitted bids is disclosed at auction and when the maximum penalty is larger. When only the winner’s identity is disclosed (or the winner’s identity and bid), cartels do not benefit from mediation. Our main result characterizes the cartel-optimal equilibrium with two symmetric bidders when both bids are disclosed. The optimal equilibrium involves extensive randomization and displays tied bids and high winning bids with positive probability, even when the maximum penalty is very small. The stationary mediation schemes we consider are always more profitable for the cartel than bid rotation.

  PublisherDOI

Frequent coauthors

• Sylvain Chassang

  Princeton University

  18 shared

• Kei Kawai

  University of California, Berkeley

  12 shared

• Martin C. Schmalz

  10 shared

• Jun Nakabayashi

  10 shared

• Avidit Acharya

  7 shared

• Jun Nakabayashi

  Fujifilm (Japan)

  1 shared

• Takuo Sugaya

  Stanford University

  1 shared

• Edoardo Grillo

  University of Padua

  1 shared

Education

• Ph.D.

  Princeton University