Google Inc. is poised to make voluntary concessions that willend a 20-month U.S. antitrust probe of its business practiceswithout any enforcement action, two people familiar with the mattersaid.

Google, which has been under investigation by the Federal TradeCommission, is preparing a letter promising not to copy contentfrom rival websites without permission and to allow advertisers tocompare Google's ad-campaign data with performance on otherInternet search engines, one of the people said Dec. 16. That willclose the investigation without a lawsuit or settlement, said thepeople, who asked not to be identified because the matter isn'tpublic.

An end to the probe without any enforcement action would be ablow to Google's competitors including Microsoft Corp., Yelp Inc.and Expedia Inc., which formed an alliance to press the agency toact. They claim Google's dominance of Internet search, combinedwith favoring its own services in answers to queries, violatesantitrust laws and impedes competition.