That earlier push was bipartisan. On Oct. 28, Warren and Sen. John Curtis, R-Utah, wrote to Kalshi CEO Tarek Mansour and Polymarket CEO Shayne Coplan asking how the companies stop candidates, campaign staff and others with material nonpublic information from trading election contracts.
What Warren and Curtis asked Kalshi and Polymarket
“We are particularly troubled by election-related event contracts,” the senators wrote. “Event contracts tied to elections receive prominent coverage and are treated by some observers as indicators of political momentum. There are also documented cases of candidates betting on their own races, which undermines the overall integrity of the American electoral process.”
The letter cited candidates who traded on their own contests on Kalshi, including a February 2026 California gubernatorial race, and pointed to research alleging wash trading and volume manipulation on Polymarket. It also referenced an NPR investigation of campaign insiders who said they traded ahead of polling releases.
“The identification of isolated instances of improper trading does not demonstrate that these markets are adequately protected,” Warren and Curtis wrote. “Instead, it raises serious questions about how much similar activity may be going undetected.” They asked for written answers by Election Day, Nov. 3.
Kalshi’s head of enforcement, Robert DeNault, told Business Insider that the company “proactively blocks candidates and campaign staff from trading to protect market integrity.” Polymarket did not respond to that request for comment.
Crypto sits inside the same Banking gavel
Prediction markets are not a side show for bitcoin readers. Polymarket is a crypto-native venue that settled U.S. access through a CFTC-registered exchange after years offshore, while Kalshi operates as a designated contract market under the Commodity Futures Trading Commission. Both sit in the orbit of the same committee Warren is about to run.
Under Chairman Michael S. Selig, the CFTC has spent 2026 defending those platforms against state gambling laws, suing Wisconsin, New York and others to assert exclusive federal jurisdiction over event contracts on registered exchanges. A Democratic Banking chair targeting what her aide called a Wild West lands as the counterweight to that stance.
Warren has been one of crypto’s sharpest critics on the Hill. She opposed the CLARITY Act market structure bill, which failed a Senate cloture vote 49-50 on Sept. 15, and analysts have argued a Democratic Congress leaves little path for a Republican rewrite. House Democrats are already sketching their own package with a bigger SEC role.
The aide’s broader agenda for Warren also includes affordability legislation, a push to cap credit card interest rates, AI chip export controls, and oversight of Trump administration officials, Wall Street CEOs, Big Tech executives and anyone tied to the Trump family’s crypto ventures.
The test for prediction markets is no longer whether Trump-era regulators will keep clearing the way. It is whether Warren, with subpoena power and the Banking gavel, turns the Kalshi and Polymarket letter into hearings that rewrite how election and event contracts are policed.
This post Elizabeth Warren Plans Prediction Market Crackdown as She Prepares to Chair Senate Banking first appeared on Bitcoin Magazine and is written by Micah Zimmerman.