Ronald Acuña Jr. becomes first MLB player to promote prediction market with Kalshi deal
Baseball star Ronald Acuña Jr. has partnered with Kalshi, becoming the first MLB player to promote a prediction market. The deal was announced October 8. It follows team-level agreements between the New York Mets and Novig and the New York Yankees and Polymarket. A Reddit post referenced the partnership with a comment about betting on individual at-bats. The arrangement marks Kalshi's entry into athlete-driven marketing.
Kalshi is now the third prediction market platform to land a major athlete partnership, after Polymarket's $15 million annual deal with LeBron James and Novig's equity-for-endorsement arrangement with Sydney Sweeney. Kalshi must prove this quarter that Acuña Jr. converts fans into funded accounts at rates that justify the spend. The deal's structure matters: if Kalshi matched Polymarket's fixed cash model, it burned scarce capital against a $40 billion rival.
If it copied Novig's equity approach, it bet on conversion over upfront cost. The first platform to publish funded-account data from its celebrity campaign will set the talent cost structure every competitor must match for the next funding cycle. Acuña Jr.'s performance as a marketing asset will determine whether Kalshi keeps buying stars or exits celebrity marketing entirely.