Philadelphia 76ers forward LeBron James posted a 14-second video on X and Instagram showing him entering a stylized Polymarket office with the caption "Welcome to Polymarket HQ. Coming soon," and "In partnership with @Polymarket." This appears to be the first reveal of a formal relationship, though the exact nature (advertisement, ambassador, investor, or sponsorship) remains unclear. His recent free agency decision to join the 76ers led to $273 million in related contracts traded across prediction market platforms, with Polymarket's international platform seeing over $43 million in volume.