A Bloomberg Businessweek analysis published this month put a hard number on a suspicion that has trailed Polymarket all year: roughly $200 million worth of trades on the exchange carry the markers usually associated with insider activity. The figure is drawn from about 34,000 transactions that the prediction-market analytics firm Polysights flagged between August 2025 and June 2026, and the review found that trades fitting the pattern grew more common starting in January.
The important word is flagged. A flag is a statistical guess, not a finding: 34,000 flags do not establish 34,000 violations, and Polymarket has not been accused of wrongdoing over any specific trade in the set. What the number does show is scale. Prediction-market volume has grown fast enough that the job of watching it for abuse has become an institutional problem, the kind stock exchanges spend heavily to solve.
What a flag actually measures
Polysights does not read minds; it reads behavior. The platform scores each trade across eight metrics, then flags the ones that cluster at the extremes. The inputs are the tells a compliance desk would look for by hand: how much money the account is staking, how recently the account was created, how long the odds were at the moment the trader bought in, and how tightly the trader's volume is concentrated in one or a handful of markets. A brand-new account that stakes a large sum on a long-shot outcome and touches almost nothing else is the archetype the score is built to catch. None of those signals is proof on its own; a confident trader and an informed one can look identical from the outside, which is exactly why a flag is a starting point for review rather than a conclusion.
The regulators have started to move
The surveillance question is no longer academic. The US Commodity Futures Trading Commission opened a broad investigation into Polymarket over the summer, and the agency's enforcement chief has said he intends to hire more staff specifically to bring cases against traders on newer venues like Polymarket and Kalshi. A House oversight panel opened its own inquiry into insider-trading risk on prediction markets in May, after a US soldier was charged in April in one of the first criminal cases tied to trading on event outcomes.
Rival Kalshi has spent the interval building the machinery Polymarket is now being measured against. A spokesperson, Laura Frank, said the exchange has spent years building custom trade-surveillance and enforcement systems "similar to those used in the stock market," and it requires identity verification before a user can trade. That apparatus has already produced referrals: Kalshi flagged trading by former congressman George Santos on markets tied to the State of the Union and passed it to the CFTC, examined activity by a former White House teleprompter operator on presidential-speech markets, and fined a MrBeast employee and a California gubernatorial candidate over trades earlier in the year. Those are Kalshi cases, not Polymarket's — but they are the yardstick, and they are why the $200 million figure landed as hard as it did.
