Microsoft shares rode the continuing bull market up 68 cents, 2.5 percent, to a new 52-week high of $28.22 Thursday. Broader market indices were also up. Microsoft is a component of several of these, including the Dow Jones Industrial Average (up 0.81 percent), the S&P 500 (up 0.95 percent) and the Nasdaq 100 (up 1.61 percent).

Alan Davis, an analyst with D.A. Davidson & Co., said the scant news on Microsoft Thursday -- a small acquisition and new labels for Vista-ready products -- didn't seem to be catalysts for the stock's performance. He did see solid numbers out of consumer stocks such as McDonald's and broadening positive expectations about Microsoft's forthcoming new products, Vista and Office 2007.

Davis, who has a "buy" rating on MSFT and last week bumped up his price target to $32, said shares of the company have tended to rise in advance of the launch of major operating systems as investors factor their expectations about future sales into the price.

He also noted that the tech-heavy Nasdaq traditionally does well in the fourth quarter.

"If history repeats itself, that's another tailwind" for Microsoft, Davis said.