SAN FRANCISCO (AP) — IBM Corp. ushered in Virginia Rometty as the company's first-ever female CEO on Tuesday, as Sam Palmisano stepped down from the position.

Palmisano, who turned 60 this year, has been CEO for nearly a decade. He will stay on as chairman. Virginia "Ginni" Rometty, 54, is in charge of IBM's sales and marketing, and has long been whispered about by industry watchers as Palmisano's likely heir.

With Rometty's appointment, effective Jan. 1, women will be in charge of two of the world's largest technology companies.

Last month, Meg Whitman was named CEO of Hewlett-Packard Co. Whitman joined eBay Inc. when it was a fledgling startup during the dot-com boom and guided it to become an Internet auction powerhouse and later ran for California governor.

While Whitman's HP is a sprawling company in disarray, Rometty will inherit a finely tuned IBM whose focus on the high-margin businesses of technology services and software has helped it thrive.

IBM's move was unexpected. Palmisano had tamped down earlier talk of his retirement, insisting that he wanted to stay on as chief. In rare public comments, he said last year that he was "not going anywhere" and that there's no formal policy at IBM dictating when a CEO should retire.

Palmisano in a statement said that Rometty has led some of IBM's most important businesses, and was instrumental in the formation of IBM's business services division. She oversaw IBM's $3.5 billion purchase of PricewaterhouseCoopers' consulting business in 2002, which is a key element of a strategy that has made IBM a heavily copied company. She is "more than a superb operational executive," Palmisano said.

"She brings to the role of CEO a unique combination of vision, client focus, unrelenting drive, and passion for IBMers and the company's future," Palmisano said. "I know the board agrees with me that Ginni is the ideal CEO to lead IBM into its second century."

Investors had liked the idea of Palmisano staying at the helm.

IBM shares fell $1.59, or 0.9 percent, to $178.77 in extended trading, after the change was announced.