In a brief statement, Oracle CEO Larry Ellison said: "Greg has told us he's looking at a terrific professional opportunity," said Oracle CEO Larry Ellison. "We wish him well."
Maffei said: "My resignation from Oracle is not a reflection on the company, its executives or employees. And I wish Oracle and my former co-workers the very best."
In July, Maffei succeeded Harry L. You, who left Oracle after serving only eight months as CFO to become CEO of BearingPoint.
Maffei came to Oracle after five years as CEO of 360Networks, a regional fiber optic network provider to telephone companies, businesses and federal agencies. Before that turn, Maffei was CFO of Microsoft from July 1997 to January 2000.
Maffei had also shared president duties with Charles Phillips and Safra Catz. Taking on the CFO duties should seem familiar to Catz, who became Oracle's default CFO after You left in March 2005.
Paul Hamerman, an enterprise applications analyst for Forrester Research, said current Chairman Jeff Henley, Oracle's CFO for 13 years, left a tough act to follow.
"Jeff was really someone who helped build the company and was CFO for a long time," Hamerman said. "Harry You was a fine CFO but just got a better offer. This situation with Greg Maffei is different. My sense is he clashed with the other top level execs."