Polymarket investigates suspicious bets placed hours before NYT/Siena polls
Polymarket has launched an internal investigation after researchers flagged a trader who made more than $257,000 on Senate race bets placed shortly before two New York Times/Siena College polls were made public.
The pattern of trades began on October 30, when more than $2 million was deposited into an anonymous crypto wallet. The account then placed a series of large bets on Polymarket, including a $191,277 wager on Nebraska Republican Senator Pete Ricketts winning re-election.
The bet was placed on October 31, hours before a New York Times/Siena poll showed Ricketts leading by six points. Before the poll was released, the market gave Ricketts a 67% chance of winning. After the poll, those odds rose to 79%, turning the position into a profit of more than $77,000.
The same trader also put more than $622,000 behind the Democratic nominee in the Michigan Senate race. After a subsequent NYT/Siena poll was released, that position produced profits exceeding $180,000. The account cleared more than $257,000 across the two races.
Requires further investigation.
Brett Goldstein, the Vanderbilt researcher involved in the work, was careful not to accuse anyone outright. He said the activity was hard to dismiss as simple coincidence and deserved a closer look. Polymarket confirmed it had detected the trades and begun its own review but did not announce any conclusions or penalties.
The research also covered Kalshi, the other major prediction market named in the findings. Kalshi declined to comment. Major media polls are scheduled events, and a handful of people, including pollsters, editors and production staff, see results before publication. The funding came through an anonymous wallet, which means the trades are visible on-chain, but the identity behind them is not.
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