Talking Their Way Out of a Price War: Communication, Collusion and Monitoring in LLM Pricing Agents
Leo Bogdaneris · Team Leo Bogdaneris (solo)
Submitted to AI Collusion Research Sprint. Sprint projects are early-stage work by participants, not Apart Research publications.
Two Qwen3-8B sellers play a repeated pricing game in a pre-registered, placebo-controlled factorial (450 episodes). A private message channel is by far the strongest collusion lever (+1.77 on an index where 0 is Nash and 1 is monopoly), but it mostly ends a below-Nash price war, settling prices near 1.55 and costing consumers 0.42 surplus per period. Agents’ words overstate their prices. Activation probes detect collusion but are worse than a classifier on the visible price history.
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Cite this project
@misc{bogdaneris2026talking,
title = {{Talking Their Way Out of a Price War: Communication, Collusion and Monitoring in LLM Pricing Agents}},
author = {Leo Bogdaneris},
year = {2026},
month = oct,
note = {Submitted to AI Collusion Research Sprint, an Apart Research Sprint},
howpublished = {\url{https://apartresearch.com/sprints/projects/talking-their-way-out-of-a-price-war-communication-collusion-and-monitoring-in-llm-pricing-agents-usts}},
url = {https://apartresearch.com/sprints/projects/talking-their-way-out-of-a-price-war-communication-collusion-and-monitoring-in-llm-pricing-agents-usts}
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