Cause of cross-platform performance gap (Kalshi vs. Polymarket)

Determine whether the substantially smaller losses observed for Cohort 1 models on Polymarket during the Feb 9–Mar 9, 2026 window, relative to their concurrent Kalshi performance, are primarily attributable to agents’ market selection ability in the discovery-based Polymarket implementation or to more favorable market pricing conditions on Polymarket.

Background

The study reports a pronounced contrast between platforms: across the same Feb 9–Mar 9 period, Cohort 1 averaged −22.6% on Kalshi but only −1.1% on Polymarket. Polymarket allows discovery-based market selection, whereas Kalshi uses a curated market set.

The authors explicitly note that the observed difference could arise from either improved opportunity selection by agents on Polymarket or from different pricing dynamics on that exchange, and that current data do not allow a clean separation of these effects.