SAN FRANCISCO, April 27 — Microsoft reported strong third-quarter revenue growth on Thursday, but analysts said the company also telegraphed a significant increase in spending, an indication that it was preparing to take on its big online rivals, Google and Yahoo.
The company reported a 13 percent increase in sales for the quarter, to $10.9 billion, and a 16 percent rise in net income, to $2.98 billion, or 31 cents a share, from $2.56 billion, or 28 cents, in the period a year earlier.
The earnings were 2 cents a share below what analysts surveyed by Thomson First Call had forecast.
The chief financial officer for Microsoft, Chris Liddell, said: "Over all for the quarter, we are very happy with the continued market momentum we're seeing. Revenue is accelerating for the year."
Despite a bullish stance on revenue, Microsoft evidently surprised analysts by predicting significantly higher expenses in the next fiscal year. Its shares, which had gained 15 cents, to $27.25, in regular trading, fell on the expectation of higher expenses, dropping more than 6 percent after hours, to $25.50.
Executives also said they did not see any immediate increase in profit on the horizon even as Microsoft prepared for its largest release of new products in more than five years.
The company said once again that the update for its new operating system software, Windows Vista, would not be available until January.
For the first time, the company offered guidance on the coming year; its 2007 fiscal year starts in July.
Microsoft said revenue for 2007 would be $49.5 billion to $50.5 billion, with earnings expected to be $1.36 to $1.41 a share. Financial analysts were forecasting $1.53 a share. That guidance created some concern among securities analysts in a conference call with Mr. Liddell.
Richard G. Sherlund of Goldman Sachs, in a comment during the conference, said, "There is something really big here that we haven't put our fingers on."
Other analysts were more direct in their assessment.
"It looks like Microsoft is going to war with Google, and trying to get their product development back in track," said Eugene Munster of Piper Jaffray.
According to Mark Stahlman of Caris & Company, the fact that Microsoft plans to spend significantly more in 2007 was an indication of renewed aggressiveness in its competitive strategy and an indication that the company was returning to the kind of actions it exhibited before the Justice Department's antitrust lawsuit in the mid- and late 1990's.
"It's pretty clear that Bill is running the company again," Mr. Stahlman said, referring to Bill Gates, "and they are going to remake the business. They are being much more combative and much more strategically managed."
After Microsoft released its report, Mr. Sherlund issued a research note saying it appeared that the company planned to spend $2.4 billion more than he had expected in the 2007 fiscal year. He pointed to the costs of building the new Windows and Office Live online services, both intended to reposition the company to compete against Google and Yahoo.
When confronted with that figure during the question-and-answer session with analysts Thursday, Mr. Liddell only partly disputed the conclusion of several of them that Microsoft had begun preparing to "go to war" with its online search rivals.
"I would characterize it as a broad-based approach," he said. "There are some big numbers there, that is certainly true."
Several other analysts noted that Microsoft's expenses appeared to be running away even before 2007, many of them focusing on what they called "margin compression."
"It looks like a mess," said Brendan Barnicle, an analyst with Pacific Crest Securities, "and the big issue is margins and expenses, the big issue is the bottom line. It makes it hard to get very excited about the company's near-term prospects."
During the conference call, Mr. Liddell was optimistic about progress in the introduction of the next-generation Xbox 360 video game player. He said that a significant part of the increased spending this year was related to a push Microsoft is making in an effort to capitalize on a delay in Sony's PlayStation 3.
Microsoft now says it will ship 5 million to 5.5 million of the new Xbox systems in 2006. Sales of Xbox rose 85 percent, to $1.06 billion, in the quarter.
The company also noted that its search ad revenue fell during the quarter as it tried to shift its online advertising away from a service provided by Yahoo to the newly developed MSN Ad Center system.
It also reported that losses widened in its home and entertainment division, the Mobile and Embedded Devices Group, and the MSN service.
Sales of Windows for PC's increased 7.5 percent, to $3.19 billion, in the quarter, while office sales rose 5 percent, to $2.95 billion.