# LOB-Impact Benchmark: Emergent Market Impact in Generative Limit Order Book Models > Source: > Published: 2026-10-30 01:30:01+00:00 Realistic market impact is essential for generative limit order book (LOB) models to serve as world models for trading agents. If a simulator misprices this mechanism, agents learn policies that are optimal in the simulator but wrong in the real market. Existing metrics assess generated streams pure