Shippers are starting to delegate carrier selection to large language model (LLM) agents. This study explores the effects of such delegation on freight matching markets and which platform design choices can control it. We conducted agent-based simulations with fifty shipper agents built on commercial LLMs from OpenAI (GPT), Anthropic (Claude), and Google (Gemini) to procure truckload capacity over thirty days. The market implements digital freight matching rules: each load is offered according to the shipper's ranked list of carriers (waterfall tendering), carriers have daily capacity limits, spot prices respond to congestion, and carrier ratings accumulate with transactions.
We identified three risks and one effective remedy. Agents converged simultaneously: for a fixed sampled carrier population, the same carrier was the modal first choice for every model on day one, attracting up to 76% of requests. Since each agent picks from its own randomly drawn list of displayed candidates, the platform controls how many options each shipper sees; concentration rose sharply once lists exceeded about ten carriers, with onset differing across models.
The dominant carriers varied widely across sampled markets, and displaying true quality instead of estimated ratings did not change either the level or variability of concentration (by design, quality affects only what agents see, never delivery outcomes). To mitigate these risks, disclosing each carrier's remaining daily capacity reduced concentration by a third and doubled shipper surplus, while vendor diversification, list-order randomization, and popularity display showed no clearly detectable effect. Platform information design is the key lever, ahead of model choice or model regulation.
Blogger's Review: This article highlights the concentration risks posed by LLMs in freight markets and underscores the significance of information design. As algorithmic decision-making becomes more prevalent, effectively managing carrier selection will have profound implications for market fairness and efficiency. By promoting transparency in information disclosure, shippers can make better choices, enhancing the overall operational efficiency of the market.