Oct. 28 (Bloomberg) -- Yahoo! Inc. handled a larger chunk of U.S. Internet searches last month while Microsoft Corp. lost market share, according to researcher ComScore Inc.

Yahoo had about 20.2 percent of queries in September, up from 19.6 percent in August, Reston, Virginia-based ComScore said today in an e-mail. Microsoft's share fell to 8.5 percent from 8.9 percent. Google Inc. handled 62.9 percent, compared with 63 percent in August.

The companies are competing for users as growth in the Internet advertising market slows. The credit crisis may cost the industry $6.7 billion in lost sales through 2010, curbing growth to less than 20 percent next year, according to Collins Stewart Plc. To bolster sales, Yahoo plans to show some Web- search ads sold by Google, a deal under scrutiny from the U.S. Justice Department.

The total number of searches in September was 11.8 billion, compared with 11.7 billion in August, ComScore said.

Yahoo, based in Sunnyvale, California, climbed 78 cents, or 6.7 percent, to $12.36 today in Nasdaq Stock Market trading. Microsoft gained $1.92 to $23.10, while Google added $39.26, or 12 percent, to $368.75.

To contact the reporter on this story: Vivek Shankar in San Francisco at vshankar3@bloomberg.net

Last Updated: October 28, 2008 17:30 EDT