Privacy fears sparked by Google DoubleClick buy

Several companies, including AT&T, Microsoft and Yahoo!, are encouraging regulators to take a close look at Google's planned purchase of online ad company DoubleClick.

Although the companies have yet to file any formal objections with regulators in Europe or the US, they are beginning to publicly voice their concerns, according to a source close to one of them.

If the deal goes through, Google would account for 80 per cent of the ads served up on the internet, the source said.

Google announced its plans to acquire DoubleClick for $3.1bn on Friday. Microsoft had also been in the running to acquire DoubleClick.

In a statement, Microsoft general counsel Brad Smith called for regulators to give the deal a hard look.

Smith said: "This proposed acquisition raises serious competition and privacy concerns in that it gives the Google DoubleClick combination unprecedented control in the delivery of online advertising, and access to a huge amount of consumer information by tracking what customers do online. We think this merger deserves close scrutiny from regulatory authorities to ensure a competitive online advertising market."

Google could not immediately be reached for comment. A Yahoo! representative declined to comment.

Google is buying DoubleClick from San Francisco-based private equity firm Hellman & Friedman, which acquired it two years ago for $1.1bn, and JMI Equity and Management. The deal is subject to regulatory approval.

David Drummond, senior vice president of corporate development at Google, said he is confident antitrust and other regulators would approve the agreement.

Ina Fried writes for CNET News.com