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Comer's letters, sent Friday to Polymarket CEO Shayne Coplan and Kalshi CEO Tarek Mansour, ask both companies to turn over documents shedding light on their identity verification procedures, how they police geographic restrictions, and what systems they use to flag abnormal trading patterns, CNBC reported.
Comer told CNBC's "Squawk Box" that if the companies resist providing information, subpoenas will follow. "We'll request information, and if we have trouble getting it, then a subpoena will follow," Comer said on Fox Business earlier this week. He set a deadline of June 5 for both companies to respond.
The probe was preceded by a letter from seven House Democrats, led by Rep. Chris Pappas of New Hampshire, calling on Comer to open a formal investigation. In his letter, Pappas cited a pattern of suspicious trades tied to U.S. and Israeli military operations against Iran: a single trader made nearly $1 million with a 93% success rate placing bets hours before strikes in Oct. 2024, June 2025, and Feb. 2026; 38 accounts netted more than $2 million on the Feb. 28 strikes alone after being preloaded with funds the preceding week; and at least 50 newly created accounts placed coordinated bets on a U.S.-Iran ceasefire on April 7, some opened minutes before the announcement.
