What Happened
Reuters reported Friday that top prediction-market platforms Kalshi and Polymarket have seen a surge in suspicious trades this year as their popularity and trading volumes explode.
Kalshi has probed and flagged more than 400 suspicious trades since the start of the year, more than twice the number it investigated during all of last year, two sources told Reuters. Polymarket has also seen a significant increase in flagged suspicious trades, another source said.
The money is getting enormous. Reuters says Kalshi's annualized trading volume has more than tripled over six months to $178 billion, while Polymarket's monthly notional trading volume reached about $10.3 billion in April across its offshore exchange and U.S. platform.
Why This Matters
Prediction markets let users buy and sell yes-or-no contracts tied to real-world events: elections, economic policy, sports and other outcomes. They can be useful signals. They can also become very expensive scoreboards for people who know something early.
Reuters quoted former SEC commissioner and Stanford Law professor Joseph Grundfest saying suspicious trading is harder to police here than ordinary corporate insider trading, because the equivalent data can be difficult or impossible to collect in some prediction markets.
The Dumb Part With The Reality Casino
The dumb part is the marketing glow around "the wisdom of crowds" when some members of the crowd may be holding the answer key under the table.
If a market pays people for being right about future events, then anyone with confidential information has a flashing neon incentive to cash in. That is not magic forecasting. That is a game show where someone in the booth might be texting contestants.
The Bottom Line
Reuters says both Kalshi and Polymarket have recently updated rules and safeguards, including measures aimed at confidential information and illegal tips. The CFTC has also begun work on prediction-market regulations.
Good. Because once the internet turns public events into tradeable contracts, "everybody please be normal" is not a compliance program.
Sources
Reuters: Prediction markets see surge in suspicious trades as popularity explodes
CFTC: Prediction market regulation press release