U.S. Sens. Elizabeth Warren (D-MA) and John Curtis (R-UT) are seeking information from Kalshi and Polymarket about how they oversee election-related prediction markets.
In letters to Kalshi CEO Tarek Monsour and Polymarket CEO Shayne Coplan, the senators requesting information about the companies’ efforts to prevent insider trading, market manipulation, and wagers based on material nonpublic information.
“We are particularly troubled by election-related event contracts. Event contracts tied to elections receive prominent coverage and are treated by some observers as indicators of political momentum,” wrote the senators. “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 several cases where political candidates traded on their own races on Kalshi’s prediction market platform. It also noted instances of what appeared to be significant trading volume manipulation on Polymarket. Overall, they are concerned about election integrity and the degree to which improper election-related transactions have remained undetected.
“A separate NPR investigation described campaign insiders who said they profited by trading before the release of polling information; NPR reported verifying at least one trade against prediction-market records,” the Senators wrote. “That concern is particularly acute as Election Day approaches, when confidential campaign decisions, internal polling, and election-administration information may have immediate financial value and the impact of election-related event contracts on the public’s perception of races is maximally influential.”
Warren and Curtis added that they are skeptical that the companies can police these even contracts with effective scrutiny and meaningful accountability.
“The identification of isolated instances of improper trading does not demonstrate that these markets are adequately protected. Instead, it raises serious questions about how much similar activity may be going undetected,” they wrote.
The senators requested responses to their answers by Election Day on Nov. 3.