Kalshi ran up a $3.24 billion day on September 27, capping a stretch of explosive growth that’s turned prediction markets into real sportsbook competition. The weekly total hit $15.27 billion, and the sector moved $8.5 billion in notional volume during NFL Week 3 alone.
Cool. Great. Love the growth story.
Except a CNBC investigation published September 30 found experts asking the question nobody asked mid-celebration: is any of this real? Analyst Beni flagged something uglier in Kalshi’s ether perpetual market. Trades of exactly $5,500 (not approximately, exactly) made up 48 to 58 percent of notional volume on four days in September. The ratio between that market’s 24-hour volume and its open interest hit 174 to 1.
A healthy market does not run on a conveyor belt of identical trade sizes.
Kalshi’s defense: its market-maker program pays for resting liquidity. The company told Prediction News the repeated sizes “came from market makers posting fixed quotes that faster traders kept hitting.” Maybe. The CFTC wanted a closer look, and Kalshi shut down its Volume Incentive Program — originally slated to run through October 2027 — rather than feed whatever this is.
CNBC stopped short of calling it proven wash-trading, and so has everyone else quoted in the piece. It’s a credible, sourced concern, not a verdict, and Kalshi denies it outright while admitting it’s tracking “hundreds of users” tied to the trades.
The platforms rolled out the celebrity treatment anyway. LeBron James fronted a Polymarket blitz alongside Sydney Sweeney, Marshawn Lynch, and Derek Jeter, teasing a fake “Polymarket HQ” like a theme park ride. None of them have anything to do with how markets trade, but it’s a hell of a marketing budget for a company whose incentive program just got pulled under regulatory heat.
The regulatory filing confirming the shutdown is public record:
Numbers that big were always going to get a closer look eventually. Turns out eventually was this week, right as the confetti was still falling.
