April 16 (Bloomberg) -- Microsoft Corp. and AT&T Inc. urged regulators to review Google Inc.'s $3.1 billion purchase of DoubleClick Inc., saying the acquisition gives the company too much control in the Internet advertising market.

The deal should be ``stringently'' reviewed by antitrust authorities because Google is positioning itself as the sole broker of online ads, AT&T said in an e-mailed statement today. Microsoft said the purchase of New York-based DoubleClick deserves ``close review and scrutiny.''

``Our competitors including Google have been quick to urge antitrust authorities to scrutinize our practices and new products,'' Brad Smith, Microsoft's general counsel, said in an interview. ``I don't think it's ironic for us to suggest that the antitrust rules should in fact apply to everyone.''

DoubleClick extends Google's lead over rivals in the $28.8 billion global online ad market and bolsters its efforts to expand beyond the plain-text ads it shows next to Internet search results. Companies such as MTV Networks and Sports Illustrated use DoubleClick's Dart program to place display ads on their Web sites and monitor how many customers they reach.

``This transaction raises some significant competitive issues and we expect the government will look into it,'' said Ed Adler, a Time Warner Inc. spokesman.

`Tremendous Choice'

Google said after announcing the purchase on April 13 that it is confident the deal will be approved by regulators.

``There remains tremendous choice'' on the Internet, Google Vice President Tim Armstrong said. ``Users tend to switch products based on how well the products perform for them.''

Shares of Mountain View, California-based Google advanced $7.98, or 1.7 percent, to $474.27 at 4 p.m. New York time in Nasdaq Stock Market trading. Shares of Redmond, Washington-based Microsoft gained 12 cents to $28.73, while shares of San Antonio- based AT&T climbed 42 cents to $39.26.

Microsoft itself has been found to violate antitrust laws in the U.S. and Europe. A judge ruled in 2000 that the software maker illegally defended its Windows monopoly by requiring Internet service providers to feature its Web browser. In Europe, regulators said the company quashed competition for server programs as well as Internet video and audio software.

``Our real concern is about this very substantial concentration that this acquisition will create,'' Smith said.

He said the purchase would give Google more than 80 percent of the market for ads that are displayed on third-party sites across the Web.

Microsoft also was one of Google's competitors in bidding to buy DoubleClick, the Wall Street Journal reported today, citing unidentified people familiar with the matter.

Too Much?

Google's announcement also sparked concern from analysts that the company may be paying too much for DoubleClick. Google executives declined to disclose DoubleClick's financial results or give details on plans for integrating the company's products.

``They just don't tell you anything,'' said Gene Munster, an analyst at Piper Jaffray & Co. in Minneapolis. He rates the shares ``outperform'' and doesn't own them.

Munster estimates that DoubleClick will have sales of $330 million this year and that Google may lose about $150 million a year in interest income.

Anthony Noto, an analyst at Goldman, Sachs & Co., said in a note to clients that while the price is too much for DoubleClick's business today, it could be justified over time. The acquisition will let Google sell packages to customers that bundle text ads tied to search results with so-called display ads that often include pictures or video, he said.

`Excessive Price'

The purchase, scheduled to close by the end of the year, highlights the soaring valuation for Internet companies that have managed to strike a chord with users and advertisers. Google bought video-sharing Web site YouTube for $1.65 billion last year. Facebook, a social networking site competing with MySpace, last year turned down a $1 billion offer from Yahoo! Inc.

``Google did not want anyone else buying this asset,'' said Scott Kessler, an equity analyst at Standard & Poor's in New York. ``It's an excessive price.''

The purchase may also spark interest in Seattle-based aQuantive Inc. as an acquisition target, analysts said today. At least three brokerages, including CIBC World Markets, JPMorgan Chase & Co. and UBS AG, upgraded the shares today.

Shares of aQuantive, which offers it own ad measurement program, rose $3.49, or 12 percent, to $32.01 in Nasdaq trading.

To contact the reporter on this story: Jonathan Thaw in San Francisco at jthaw@bloomberg.net; Ville Heiskanen in New York at vheiskanen@bloomberg.net

Last Updated: April 16, 2007 17:04 EDT