Microsoft Corp. (MSFT) said its chief financial officer, Chris Liddell, plans to leave the software company by the end of the year to look for a new job.

The company said Liddell, 51, who has held the position since 2005, will be succeeded by Peter Klein, 47, who is CFO of Microsoft's business division.

Liddell informed the company of his decision to resign last Thursday, according to a company filing with the Securities and Exchange Commission. He wants to expand his career beyond the duties of a CFO and plans to explore job possibilities in private equity and other areas, according to a Microsoft spokesman.

"He's going to take some time to figure out what he wants to do," said the spokesman, who said Liddell's departure was his own choice.

The spokesman said Liddell wasn't available for an interview.

Since joining Microsoft in 2005, Liddell became well regarded among Wall Street investors and analysts for helping to guide it through a bumpy period as it shifted to being a more mature company from the hot growth story it once was.

During his tenure, Liddell has made efforts to reduce Microsoft's huge stockpile of cash by boosting investor dividends and stock buybacks, and the company raised debt for the first time in its history. In the past fiscal year alone, Microsoft said it returned $14 billion to shareholders through stock buybacks and dividends.

Yet Microsoft's stock increased only modestly since Liddell joined the company, as investors have fretted about the durability of Microsoft's big software franchises like Windows and Office in the face of competition from Google Inc. (GOOG) and other threats. Bill Whyman, an analyst at ISI Group, said Liddell earned credibility investors even as they had trouble understanding when the payoff would come from big investments Microsoft was making in new areas like Internet search favored by CEO Steve Ballmer.

"He labored under a dominant personality who has a challenging relationship with the investor community," said Whyman. "That's a tough a job description."

Before joining Microsoft, Liddell, a native of New Zealand, served as CFO of International Paper Co. and Carter Holt Harvey Ltd. Microsoft's new CFO, Klein, joined Microsoft in 2002 and previously spent 13 years working in technology startups and a private equity firm.