Algorithmic Collusion

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Overview

Algorithmic collusion concerns software agents whose repeated decisions can sustain prices or profits above competitive levels, sometimes without explicit communication or instructions to cooperate. Researchers study this with repeated Bertrand and Cournot pricing games, electricity markets, auctions, and execution tasks, using Q-learning, deep multi-agent reinforcement learning, and language-model agents, alongside theoretical models of exploration and information. Detection and mitigation approaches include profitable-deviation and retaliation tests, trajectory analysis, audits, and changes to learning objectives or observation conditions. A central challenge is distinguishing collusion from merely high prices: outcomes depend on memory, partner persistence, and agent heterogeneity, while individual price histories or chain-of-thought monitoring may fail to reveal coordination.

Latest papers

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23 papers5 papers in the last four weeks, level with the four weeks before. 0.0% of all new papers.

  1. Is Anyone Enforcing the Cartel? What Reinforcement Learning Teaches LLM Agents in Markets

    Oct 20, 2026Hieu Tran, Hong YuAlgorithmic CollusionRL for LLM Agents

    University of Massachusetts Amherst · University of Massachusetts Lowell

  2. How language model agents reshape price competition

    Oct 15, 2026Martin Bichler, Philip Hierhager, Kassian Köck +1Algorithmic CollusionDynamic Pricing

    School of Computation, Information and Technology, Technical University of Munich, Germany.

  3. Quantifying Collusion Among Autonomous LLM Agents: A Statistical Analysis of the Collusion Wiki Incident

    Oct 3, 2026Shariq MurtuzaAlgorithmic CollusionAI Agent Security

  4. Beyond Supra-Competitive Outcomes: Collusive Behaviour in Deep Reinforcement Learning for Optimal Execution Games

    Sep 30, 2026Christos Spyridon Koulouris, Carlo CampajolaAlgorithmic CollusionMulti-Agent Reinforcement Learning

    Institute of Finance and Technology University College London Gower Street, London WC1E 6BT, United Kingdom · UZH Blockchain Center Andreasstrasse 15, 8050 Zürich, Switzerland

  5. Persistent Partners Raise Prices Among Learning Agents

    Sep 28, 2026Paul-Peter Arslan, Yubin Kim, Xiao XiaoAlgorithmic CollusionMulti-Agent Systems

    Institute For Future Technologies Devinci Higher Education · Massachusetts Institute of Technology

  6. Codetta: High-Capacity, Keyless, and Undetectable Multi-Agent Collusion

    Sep 24, 2026Qi Pang, Virginia Smith, Wenting ZhengMulti-Agent LLM SystemsAlgorithmic Collusion

    Carnegie Mellon University

  7. Algorithmic Collusion and the Complexity of Information-Value-Free Equilibria

    Sep 19, 2026Ioannis Anagnostides, Weiqiang ZhengGame TheoryAlgorithmic Collusion

    Carnegie Mellon University · Yale University

  8. Mitigating Retaliatory Algorithmic Collusion in Repeated Games

    Sep 17, 2026Karthik Sivachandran, Rohan PalejaAlgorithmic CollusionRepeated Games

    Department of Computer Science Purdue University

  9. Faithful yet Collusive: Why Chain-of-Thought Monitoring Cannot Detect Collusion in LLM Pricing Agents under Oligopolistic Competition

    Sep 16, 2026Dohun Lee, Hyunwoo ParkCoT FaithfulnessLLM Auditing

    Graduate School of Data Science, Seoul National University

  10. CABAL: Multi-Agent Simulacra for Tracing the Effects of Collusive Bidding in Peer Review

    Sep 4, 2026Jicheng Zhou, Kemou Li, Kahim Wong +5Scholarly Peer ReviewAutomated Bidding

    State Key Laboratory of Internet of Things for Smart City, University of Macau · Mila – Québec AI Institute · McGill University +2

  11. AI agents in Algorithmic Electricity Markets: On the Emergence of Tacit Collusion

    Aug 27, 2026Jakub Seredyński, Georgios TsaousoglouAlgorithmic CollusionAutomated Bidding

    Department of Applied Mathematics and Computer Science, Technical University of Denmark.

  12. Steganalysis of Adaptive Covert Collusion in Tool-Using Agent Populations: A Black-Box, Cross-Principal Approach

    Aug 3, 2026Mohamed Chahine GhanemAlgorithmic CollusionAI Agent Monitoring

    Keele University, Newcastle-Under-Lyme, U.K.

  13. Collusion with Competitive Marginals: Price-Level Audits Are Blind by Construction

    Jul 29, 2026Xin Xu, Chengrui Wu, Jiayu Lu +3Algorithmic AuditingAutomated Bidding

    Carnegie Mellon University · Zhejiang University

  14. Equilibrium stability as a driver of cooperation among Q-learners

    Jul 15, 2026Janusz M. Meylahn, Maximilian SchäferGame-Playing AgentsRepeated Games

    University of Twente, Department of Applied Mathematics, Drienerloolaan 5, 7522 NB Enschede, The Netherlands. · Institut Mines-Télécom Business School, Department of Data Analytics, Economics, and Finance. 9 Rue Charles Fourier, 91000 Evry, France.

  15. Oblivious Learning and Collusive Pricing

    Jun 3, 2026Yuhang Wu, Assaf ZeeviExploration-Exploitation TradeoffGame Theory

    Columbia Business School

  16. Failure Modes of Deep Multi-Agent RL in Asynchronous Pricing: Reproducible Triggers, Trace Diagnostics, and a Partial Fix

    Jun 3, 2026Shree Murthy, Rohan PandeyAsynchronous RLAlgorithmic Collusion

    DigitalOcean, USA

  17. Memory-Induced Supra-Competitive Outcomes Between Deep Reinforcement Learning Agents in Optimal Trade Execution

    May 19, 2026Christos Spyridon Koulouris, Carlo CampajolaAlgorithmic CollusionMemory-Augmented Agents

    Institute of Finance and Technology, University College London, Gower Street WC1E 6BT London, United Kingdom · UZH Blockchain Center, Andreasstrasse 15, 8050 Zürich, Switzerland

  18. Misspecified Estimate-then-Optimize Leads to Supra-Competitive Prices

    May 15, 2026Jackie Baek, Vivek F. Farias, Farrell WuPredict-Then-OptimizeLearning to Optimize

    Stern School of Business, New York University · Massachusetts Institute of Technology

  19. Prompt Optimization Enables Stable Algorithmic Collusion in LLM Agents

    Apr 20, 2026Yingtao TianMulti-Agent CoordinationAlgorithmic Collusion

    Sakana AI Tokyo, Japan

  20. On the Fragility of AI Agent Collusion

    Mar 18, 2026Jussi Keppo, Yuze Li, Gerry Tsoukalas +1Algorithmic CollusionMulti-Agent LLM Systems

    National University of Singapore · Boston University

  21. Algorithmic Collusion at Test Time: A Meta-game Design and Evaluation

    Feb 19, 2026Yuhong Luo, Daniel Schoepflin, Xintong WangAlgorithmic CollusionGame Theory

    Rutgers University · DIMACS, Rutgers University

  22. Individualized Algorithmic Advice as a Strategic Signal on Competitive Markets

    Nov 12, 2025Tobias R. Rebholz, Maxwell Uphoff, Christian H. R. Bernges +1Algorithmic Collusion

    Department of Psychology, University of Tübingen · Fuqua School of Business, Duke University · Department of Economics, University of Minnesota Twin Cities

  23. Algorithmic Collusion by Large Language Models

    Mar 31, 2024Sara Fish, Yannai A. Gonczarowski, Ran I. ShorrerPrompt SensitivityAlgorithmic Collusion

    †School of Engineering and Applied Sciences, Harvard University · ‡Department of Economics and Department of Computer Science, Harvard University · §Department of Economics, Penn State University