Electronic Arts ( ERTS) said its president resigned to start a private-equity business. The resignation of John Riccitiello, who oversees global publishing, online and other corporate departments, is effective immediately, although he will stay on at EA for a transition period, the Redwood City, Calif.-based video game maker said. The company said CEO Larry Probst will assume interim responsibility for Riccitiello's posts, which also include chief operating officer, while EA evaluates candidates to join its executive team. "Personally, it is time to do something different, and I intend to start a private-equity business," Riccitiello said a statement. News of Riccitiello's departure came the same day Merrill Lynch analyst Karen Russillo downgraded EA to neutral from buy on valuation. She noted that Electronic Arts' 16% stock appreciation in the past two weeks was twice that of the Nasdaq Composite, driven by Microsoft's decision to slash Xbox prices and not release sports titles this year. (Her firm hasn't done any banking with Electronic Arts.) Shares of EA fell $1.84, or 3.4%, to close Wednesday at $53.03. In after-hours trading, shares declined 55 cents, or 1%, to $52.48.