Kalshi and Polymarket volume patterns draw fresh wash-trading scrutiny
Unusual trading patterns on Kalshi and Polymarket have drawn expert scrutiny about whether reported volumes reflect genuine market activity. CNBC flagged atypical Ether perpetual futures volume on Kalshi and elevated trading in low-probability Polymarket contracts. Both CFTC-regulated platforms have rejected wash-trading allegations. The questions arrive as both venues have seen massive growth. Neither CNBC nor the platforms identified specific traders responsible for the patterns.
Traders use volume data to size liquidity risk before committing capital; persistent authenticity questions push them toward competitors with cleaner disclosures. Kalshi already surrendered its volume incentive program and faces CFTC review of $5 billion in questioned Ether perpetual trades, while Polymarket must now defend low-probability contract figures alongside its U.S. growth surge.
The scrutiny spans both platforms simultaneously, suggesting the volume-integrity issue is becoming a cross-venue narrative rather than a single-platform problem. Rivals with sharper transparency can capture migrating flow during the NFL season's peak betting window. The first venue to publish verified, single-event volume methodology will set the transparency bar the rest must clear. Unresolved questions invite regulatory scrutiny that could delay product approvals at either platform.
Joins three prior volume-integrity clusters this month — Kalshi's denied wash-trading claims, its Ether perpetual ratio hitting 174x, and its incentive-program termination — as scrutiny of headline volume figures migrates from single-platform disputes to cross-venue pattern analysis.