Google Negotiating For 5% AOL Stake; Microsoft Left Out; AOL: Google's Top Customer; America Online will still use No. 1 search engine in likely deal, sources say.(A)

Byline: BRIAN DEAGON

Google has outplayed Microsoft again, offering $1 billion for 5% of Time Warner's America Online unit, sources told Reuters and others.

Time Warner could finalize the deal next week.

It's a big blow to Microsoft, which had sought an AOL alliance as part of its plan to grab a chunk of paid search revenue when it launches adCenter on MSN early next year.

"This is not good news for Microsoft," said Gregory Markel, founder and chief executive of Infuse Creative, a search engine marketing firm.

Google, which joins the Nasdaq 100 on Monday, rose 2% to 430.15, a closing high. Time Warner edged up, while Microsoft shed …