Skip to content
Apart Research
Apart Research
Contact us
Sprint projectOct 25, 2026

One Honest Bot Is Enough: Breaking Up Price Collusion Between Learning Pricing Bots

Emediong Etuk · Team Obito

Submitted to AI Collusion Research Sprint. Sprint projects are early-stage work by participants, not Apart Research publications.

Read the report

Report: One Honest Bot Is Enough: Breaking Up Price Collusion Between Learning Pricing Bots

Open in a new tab (opens in new tab)
Code (opens in new tab)
Share

Pricing bots that learn by trial and error can quietly learn to keep prices high together, like a cartel. I tested four simple fixes, one at a time, in a standard market with two such bots (50 runs each).

Swapping just one of the two bots for an honest “no-regret” bot cut collusion by 91%, from 0.83 to 0.08 (0 = fair competition, 1 = full cartel). Forcing random prices helped only partly, adding a third seller helped a little, and hiding rival prices made collusion worse.

Reviews

Judging this Sprint?

Review “One Honest Bot Is Enough: Breaking Up Price Collusion Between Learning Pricing Bots”

Your public critique appears on the project page without your name. Reviews of strong projects are shared with funders, as you choose below.

Not shown on the project page.

Shown on the project page, without your name.

Only the Apart team reads this, and funders if you agree below.

Decline to score

Only when the quality of the writing makes the work impossible to follow. Say why in your private critique; the project page shows only that a judge declined, not why.

How much would this matter for the field if it worked? How innovative is it? For scores of 4-5: is this actually new to the field, or replicating recent work?

Scoring guide
  1. 1Negligible. No clear problem addressed, or no meaningful novelty.
  2. 2Limited. Addresses a real problem but with a generic or well-trodden approach. Incremental at best.
  3. 3Moderate. Clear problem with a reasonable approach; some novelty in framing or method beyond routine application of existing tools.
  4. 4Significant. Important problem with an original approach, or identifies a neglected problem area. A valuable contribution others could build on.
  5. 5Exceptional. Tackles a critical problem with a genuinely novel approach, or opens a new research direction. Clear theory of change. You'd be excited to share this with researchers in the area.

How sound are methodology, implementation, and findings?

Scoring guide
  1. 1Seriously flawed. Methodology broken, results uninterpretable, or implementation doesn't work.
  2. 2Weak. Approach has significant gaps: missing validation, flawed experimental design, or incomplete implementation.
  3. 3Competent. Technically solid given the short duration. Methodology makes sense, results are interpretable, limitations acknowledged, work builds toward clear conclusions.
  4. 4Strong. Thorough methodology with convincing validation. Results clearly support conclusions. Immediately useful for future work.
  5. 5Exceptional. Ambitious scope executed rigorously. Surprising findings, novel methods, or unusually robust validation.

How clearly are work, findings, and impact potential communicated?

Scoring guide
  1. 1Incomprehensible. Cannot determine what the project is actually claiming or doing.
  2. 2Hard to follow. Key information buried, missing, or diluted by excessive length. Significant effort to extract main points.
  3. 3Clear enough. Can understand the problem, approach, and results without undue effort. Core content clearly present: problem, method, findings, limitations.
  4. 4Well presented. Easy to follow, well-structured, appropriate level of detail. Target audience would get it quickly.
  5. 5Exceptionally clear. A pleasure to read. Complex ideas made accessible. Could serve as a model for how to present this type of work.
Sharing your name *

When we share a strong project with funders, your name, scores and public critique go with it, confidentially; this choice is only about whether your name is public. If you think this project deserves funding, please also endorse it: that carries the most weight.

Share my private critique with funders *

See our Privacy Policy.

  1. This is solid empirical work testing the theoretical claim from Collina et al. that one "no-regret" seller can break collusion. I think we need more of this! The variables seem sensibly controlled and it was a clear read. I would be interested in how the Hedge bot behaves if introduced only after the cartel already formed.

Cite this project

@misc{etuk2026one,
  title = {{One Honest Bot Is Enough: Breaking Up Price Collusion Between Learning Pricing Bots}},
  author = {Emediong Etuk},
  year = {2026},
  month = oct,
  note = {Submitted to AI Collusion Research Sprint, an Apart Research Sprint},
  howpublished = {\url{https://apartresearch.com/sprints/projects/one-honest-bot-is-enough-breaking-up-price-collusion-between-learning-pricing-bots-l2ri}},
  url = {https://apartresearch.com/sprints/projects/one-honest-bot-is-enough-breaking-up-price-collusion-between-learning-pricing-bots-l2ri}
}

More from AI Collusion Research Sprint

All 392 entriesBrowse all projects

A Sprint is running now

AI x Epistemics Research Sprint · Nov 13 - 15, 2026