Apollo Global Management is in advanced negotiations to buy a minority stake in Atlético Holdco, the vehicle that owns more than 70% of LaLiga club Atlético Madrid, according to people familiar with the talks. An investment would mark a rare move into professional football for the $598 billion U.S. buyout firm and could value Spain’s third-largest club at between €2.5 billion and €3 billion. The discussions began as financing for an €800 million sport-and-leisure development around the Metropolitano stadium but have shifted toward a capital increase at Atlético Holdco. Chief executive Miguel Ángel Gil Marín controls just over 50% of the holding company, while Ares Management and club chairman Enrique Cerezo hold most of the remaining shares. No formal offer has been tabled and other investors are also weighing bids, the sources said. If completed, the deal would be the second major private-equity investment in Spanish football after Ares’s €182 million purchase of a 34% stake in 2021. Atlético, which has qualified for the UEFA Champions League 12 seasons in a row, is seeking outside capital as it expands commercial projects and player spending. Both the club and Apollo declined to comment.