Prediction markets startup Kalshi has ended its advisory contract with Donald Trump Jr. after his venture capital firm, 1789 Capital, increased its stake in arch-rival Polymarket, a Kalshi spokesperson told Reuters on Thursday.
"We have mutually agreed to end Don's advisory role after his firm's significant investment in a competitor this past summer," the spokesperson said. "We are grateful for his contributions in helping us market Kalshi to more customers."
The decision was mutual, and the conversations to end the contract started in August, after 1789 Capital led Polymarket's most recent funding round. A Kalshi spokesperson said no political considerations factored into the decision.
Trump Jr. joined Kalshi as a strategic adviser in January 2025 and received an equity stake reported at the time to be worth about $300,000, according to the Financial Times. In August 2025 he joined Polymarket's advisory board, after 1789 Capital made its initial investment in the rival platform — advising both companies at once.
1789 Capital has since deepened its bet on Polymarket. The firm contributed about $300 million to a Polymarket funding round that would value the company at about $21 billion, bringing its total commitments to roughly $500 million.
Kalshi, valued at about $40 billion, and Polymarket are the two largest players in the fast-growing prediction-markets industry, where users trade contracts tied to real-world outcomes including politics, sports and economic events. The split leaves Trump Jr. firmly on the Polymarket side of the rivalry.
