Deborah Hellinger, a spokeswoman for Redwood City, Calif.- based Oracle, declined to comment beyond the statement when asked by Bloomberg about Epstein's departure.

One analyst, Jefferies & Co.'s Ross MacMillan, suggested to Bloomberg that Epstein may have stepped down because the crowded ranks at Oracle left little room for advancement. "You work in the shadow of the CEO and co-president structure," he said. "With the appointment of Hurd and an unchanging reporting structure, the question is how long he would have stayed for if there wasn't any upward momentum in his own role."

Catz has been credited by Ellison with overseeing the $10.6-billion PeopleSoft Inc. takeover in 2005, which began a huge acquisition spree. Oracle lately has depended on its purchase of Sun Microsystems Inc. last year, helping it push into the computer-hardware market.