Spotify said Tuesday that founder Daniel Ek is stepping down as CEO to become the executive chairman, in an announcement that sent its shares sliding in Tuesday trading. The Stockholm-based streaming giant said Ek will be replaced by two lieutenants who will become co-CEOs: Chief Product and Technology Officer Gustav Söderström and Chief Business Officer Alex Norström. The pair, who are also currently copresidents, will transition into their new jobs on Jan. 1 and will report to Ek. Spotify