Columbia Study Claims Polymarket Trading Volume Is Inflated by ‘Wash Trades

Your $100 Trump “Yes” bet? One in four trades on Polymarket may be hot air. Columbia University dropped a bombshell Thursday: 25% of the prediction giant’s three-year volume—$6B+—is pure wash trading, where wallets ping-pong shares to juice stats.

Prof Yash Kanoria’s 42-page autopsy (Polygon on-chain data) sliced it:
– Sports: 45% fake
– Elections: 17%
– Politics: 12%
– Crypto: 3%

Spikes synced with POLY token whispers—farmers churning for airdrop points. “Zero fees + anonymous wallets = free candy store,” Kanoria told Bloomberg. Peak: 60% fake in Dec 2023; now ~5%.

Polymarket’s October party—$2.59B volume, 477K traders, ICE $2B investment—looks half-inflated. Yet odds nailed 95%+ events. CFTC eyes return; wash trades still illegal.

CEO Shayne Coplan silent; X roasts: “My $50K volume = 12K real?” Rival Kalshi smirks with regulated $4.4B.

Bottom line: odds legit, vanity metrics not. Bet smart—wash trades don’t pay winners.