Prediction market platform Kalshi ended its advisory contract with Donald Trump Jr. after his venture capital firm, 1789 Capital, increased its stake in arch-rival Polymarket, a spokesperson for the $40 billion prediction markets startup said Thursday.
“We have mutually agreed to end Don’s advisory role after his firm’s significant investment in a competitor this past summer. We are grateful for his contributions in helping us market Kalshi to more customers,” the spokesperson said.
Conversations to end the contract started in August, after 1789 Capital led Polymarket’s most recent funding round. The decision was mutual. The company said no political considerations factored into it.
Kalshi named Trump Jr. a strategic advisor in January 2025. At the same time, Trump Jr. received a $300,000 equity stake in Kalshi.
Donald Trump Jr. became an advisor to Polymarket on Aug. 26, 2025, over a year before his venture capital firm invested $300 million in the company.
In a Sept. 21 letter, Sen. John Curtis (R-Utah) called on the Senate Judiciary Committee to examine presidential family business ties and noted, “This pattern extends to his significant financial and advisory ties to prediction-market platforms that depend on favorable federal regulatory decisions being considered by the Commodity Futures Trading Commission.”
The White House confirmed in July that a person who operated the teleprompter for President Donald Trump was placed on unpaid leave amid an insider trading probe. Karoline Leavitt, then White House press secretary, said Trump was aware of the news report and that she had spoken with him about it.
Former Rep. George Santos received a first-of-its-kind lifetime ban from Kalshi after the ex-congressman placed bets on his own attendance at a Trump speech.
Kalshi said on Aug. 28 that it had imposed a penalty of more than $71,000 on Santos and permanently banned him from its platform for betting on his own attendance at Trump’s 2026 State of the Union address.
Santos, who was expelled from the House of Representatives in 2023, was also fined by the U.S. Commodity Futures Trading Commission (CFTC) on July 31 over market manipulation related to the incident.
The Democrats, set to lead House and Senate committees after taking Congress in January, have outlined plans to investigate the Trump administration, his family’s business dealings, and companies that have done business with the White House.
Rep. Robert Garcia (D-Calif.) told CNN that members of the Trump family “should be expected to answer questions.” He said Donald Trump Jr. and Jared Kushner, Trump’s son-in-law, are possible subjects of investigations.
Representatives for 1789 Capital, Donald Trump Jr., and Polymarket did not immediately respond to a request for comment.
Reuters contributed to this report.
