IDEAS home Printed from https://ideas.repec.org/p/arx/papers/2604.18373.html

Dissecting AI Trading: Behavioral Finance and Market Bubbles

Author

Listed:
  • Shumiao Ouyang
  • Pengfei Sui

Abstract

We study how AI agents form expectations and trade in experimental asset markets. Using a simulated open-call auction populated by autonomous Large Language Model (LLM) agents, we document three main findings. First, AI agents exhibit classic behavioral patterns: a pronounced disposition effect and recency-weighted extrapolative beliefs. Second, these individual-level patterns aggregate into equilibrium dynamics that replicate classic experimental findings (Smith et al., 1988), including the predictive power of excess demand for future prices and the positive relationship between disagreement and trading volume. Third, by analyzing the agents' reasoning text through a twenty-mechanism scoring framework, we show that targeted prompt interventions causally amplify or suppress specific behavioral mechanisms, significantly altering the magnitude of market bubbles.

Suggested Citation

  • Shumiao Ouyang & Pengfei Sui, 2026. "Dissecting AI Trading: Behavioral Finance and Market Bubbles," Papers 2604.18373, arXiv.org.
    • Handle: RePEc:arx:papers:2604.18373
    as

    Download full text from publisher

    File URL: https://arxiv.org/pdf/2604.18373
    File Function: Latest version
    Download Restriction: no
    ---><---

    References listed on IDEAS

    as
    1. Hongwei Mo & Shumiao Ouyang, 2025. "(Generative) AI in Financial Economics," Journal of Chinese Economic and Business Studies, Taylor & Francis Journals, vol. 23(4), pages 509-587, October.
    2. Harrison Hong & Jeremy C. Stein, 2007. "Disagreement and the Stock Market," Journal of Economic Perspectives, American Economic Association, vol. 21(2), pages 109-128, Spring.
    3. Shefrin, Hersh & Statman, Meir, 1985. "The Disposition to Sell Winners Too Early and Ride Losers Too Long: Theory and Evidence," Journal of Finance, American Finance Association, vol. 40(3), pages 777-790, July.
    4. Jin, Lawrence J. & Sui, Pengfei, 2022. "Asset pricing with return extrapolation," Journal of Financial Economics, Elsevier, vol. 145(2), pages 273-295.
    5. Olivier J. Blanchard & Mark W. Watson, 1982. "Bubbles, Rational Expectations and Financial Markets," NBER Working Papers 0945, National Bureau of Economic Research, Inc.
    6. Shuaiyu Chen & T. Clifton Green & Huseyin Gulen & Dexin Zhou, 2024. "What Does ChatGPT Make of Historical Stock Returns? Extrapolation and Miscalibration in LLM Stock Return Forecasts," Papers 2409.11540, arXiv.org.
    7. Stefano Giglio & Matteo Maggiori & Johannes Stroebel & Stephen Utkus, 2021. "Five Facts about Beliefs and Portfolios," American Economic Review, American Economic Association, vol. 111(5), pages 1481-1522, May.
    8. repec:bla:jfinan:v:53:y:1998:i:5:p:1775-1798 is not listed on IDEAS
    9. Robin Greenwood & Andrei Shleifer, 2014. "Expectations of Returns and Expected Returns," The Review of Financial Studies, Society for Financial Studies, vol. 27(3), pages 714-746.
    10. Barberis, Nicholas & Greenwood, Robin & Jin, Lawrence & Shleifer, Andrei, 2015. "X-CAPM: An extrapolative capital asset pricing model," Journal of Financial Economics, Elsevier, vol. 115(1), pages 1-24.
    11. John J. Horton & Apostolos Filippas & Benjamin S. Manning, 2023. "Large Language Models as Simulated Economic Agents: What Can We Learn from Homo Silicus?," NBER Working Papers 31122, National Bureau of Economic Research, Inc.
    12. Barberis, Nicholas & Greenwood, Robin & Jin, Lawrence & Shleifer, Andrei, 2018. "Extrapolation and bubbles," Journal of Financial Economics, Elsevier, vol. 129(2), pages 203-227.
    13. Smith, Vernon L & Suchanek, Gerry L & Williams, Arlington W, 1988. "Bubbles, Crashes, and Endogenous Expectations in Experimental Spot Asset Markets," Econometrica, Econometric Society, vol. 56(5), pages 1119-1151, September.
    14. Stefan Palan, 2013. "A Review Of Bubbles And Crashes In Experimental Asset Markets," Journal of Economic Surveys, Wiley Blackwell, vol. 27(3), pages 570-588, July.
    Full references (including those not matched with items on IDEAS)

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Bordalo, Pedro & Gennaioli, Nicola & Kwon, Spencer Yongwook & Shleifer, Andrei, 2021. "Diagnostic bubbles," Journal of Financial Economics, Elsevier, vol. 141(3), pages 1060-1077.
    2. Barberis, Nicholas & Greenwood, Robin & Jin, Lawrence & Shleifer, Andrei, 2018. "Extrapolation and bubbles," Journal of Financial Economics, Elsevier, vol. 129(2), pages 203-227.
    3. Dahlquist, Magnus & Ibert, Markus, 2026. "Institutions’ return expectations across assets and time," Journal of Financial Economics, Elsevier, vol. 175(C).
    4. Liu, Hongqi & Peng, Cameron & Xiong, Wei A. & Xiong, Wei, 2022. "Taming the bias zoo," Journal of Financial Economics, Elsevier, vol. 143(2), pages 716-741.
    5. Cassella, Stefano & Chen, Te-Feng & Gulen, Huseyin & Liu, Yan, 2025. "Extracting extrapolative beliefs from market prices: An augmented present-value approach," Journal of Financial Economics, Elsevier, vol. 164(C).
    6. Kresta Aleš & Sedláková Michaela, 2025. "How initial price history influences expectation formation in multi-asset experimental markets: An exploratory case study," Economics and Business Review, Sciendo, vol. 11(2), pages 7-37.
    7. Barahona, Ricardo & Cassella, Stefano & Jansen, Kristy A.E. & Pezone, Vincenzo, 2026. "Do teams alleviate or exacerbate overreaction in beliefs?," Journal of Financial Economics, Elsevier, vol. 176(C).
    8. Hirota, Shinichi & Huber, Juergen & Stöckl, Thomas & Sunder, Shyam, 2022. "Speculation, money supply and price indeterminacy in financial markets: An experimental study," Journal of Economic Behavior & Organization, Elsevier, vol. 200(C), pages 1275-1296.
    9. Constantin Charles & Cary D. Frydman & Mete Kilic, 2022. "Insensitive Investors," CESifo Working Paper Series 10067, CESifo.
    10. Huihui WU & Chunpeng YANG, 2022. "Investor Sentiment, Extrapolation and Asset Pricing," Journal for Economic Forecasting, Institute for Economic Forecasting, vol. 0(4), pages 182-205, December.
    11. Matteo Benetton & Giovanni Compiani, 2024. "Investors’ Beliefs and Cryptocurrency Prices," The Review of Asset Pricing Studies, Society for Financial Studies, vol. 14(2), pages 197-236.
    12. ÅžimÅŸek, Alp, 2021. "The Macroeconomics of Financial Speculation," CEPR Discussion Papers 15733, Centre for Economic Policy Research.
    13. Liu, Hongqi & Peng, Cameron & Wei, Xiong & Wei, Xiong, 2022. "Taming the bias zoo," LSE Research Online Documents on Economics 109301, London School of Economics and Political Science, LSE Library.
    14. Shinichi Hirota & Juergen Huber & Thomas Stock & Shyam Sunder, 2015. "Investment Horizons and Price Indeterminacy in Financial Markets," Cowles Foundation Discussion Papers 2001, Cowles Foundation for Research in Economics, Yale University.
    15. Heinke, Steve & Olschewski, Sebastian & Rieskamp, Jörg, 2024. "Experiences, demand for risky investments, and implications for price dynamics," Journal of Behavioral and Experimental Finance, Elsevier, vol. 43(C).
    16. Leland Bybee, 2023. "Surveying Generative AI's Economic Expectations," Papers 2305.02823, arXiv.org, revised May 2023.
    17. Yan, Yu & Tong, Yan & Wang, Yiming, 2025. "Momentum mechanisms under heterogeneous beliefs," The North American Journal of Economics and Finance, Elsevier, vol. 75(PA).
    18. Shinichi Hirota & Juergen Huber & Thomas Stock & Shyam Sunder, 2018. "Speculation and Price Indeterminacy in Financial Markets: An Experimental Study," Cowles Foundation Discussion Papers 2134, Cowles Foundation for Research in Economics, Yale University.
    19. Wang, Hailong & Hu, Duni, 2022. "Heterogenous beliefs with sentiments and asset pricing," The North American Journal of Economics and Finance, Elsevier, vol. 63(C).
    20. Wang, Hailong & Hu, Duni, 2020. "Disagreement with procyclical beliefs and asset pricing," The North American Journal of Economics and Finance, Elsevier, vol. 51(C).

    More about this item

    NEP fields

    This paper has been announced in the following NEP Reports:

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:arx:papers:2604.18373. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: arXiv administrators (email available below). General contact details of provider: https://arxiv.org/ .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.