April 2 (Bloomberg) -- Google Inc. reported the biggest workforce reduction in its nine-year history, cutting jobs at DoubleClick Inc., the online advertising company it bought last month for $3.24 billion.

About 300 of DoubleClick's 1,200 U.S. employees were fired or placed in ``transitional'' roles, Mountain View, California- based Google said today in an e-mailed statement.

The purchase bolsters the company's technology for selling and measuring the effectiveness of display ads, which include pictures and video. DoubleClick was the largest of Google's more than 37 acquisitions. Google, owner of the world's most popular Internet search engine, completed the acquisition on March 11.

``We have been working to match and align DoubleClick employees in the U.S. with our organizational plan for the business,'' Google spokesman Brandon McCormick said.

Google fell 1 cent to $465.70 at 4 p.m. New York time in Nasdaq Stock Market trading. The stock has dropped 33 percent this year.

As part of the move, Google split DoubleClick's online marketing business, called Performics, into two units. One division sells services that help ads show up in search queries, while the other links advertisers and publishers, Google said.

Google plans to sell the search division to maintain its objectivity as a search engine, Tom Phillips, who's directing the DoubleClick integration, wrote on its official blog. The division will be run separately from Google until a buyer is found, he said.

To contact the reporters on this story: Ari Levy in San Francisco at alevy5@bloomberg.net; Connie Guglielmo in San Francisco at cguglielmo1@bloomberg.net

Last Updated: April 2, 2008 20:04 EDT