Senior members of the US Federal Trade Commission (FTC) were locked in talks last night as they decided whether to take an unprecedented step and include “consumer protection” issues in an antitrust investigation of Google’s planned takeover of DoubleClick.

The $3.1 billion (£1.56 billion) takeover of DoubleClick, the online advertising company, has suffered widespread criticism from rivals and consumer rights groups since the deal was agreed in April.

The FTC will decide next month whether its inquiry, which is at an early stage, should become a fully fledged investigation that may prompt changes to the merger agreement or the deal’s cancellation.

Until now, those who had opposed the deal on the ground that it placed too much information about consumer internet habits with one company would have been disappointed, since such issues fall outside the scope of such investigations. Yet a source said that the FTC was considering including the privacy concerns since “the worlds of competition and consumer protection are rapidly becoming intertwined”.

“The issue of privacy and consumer protection is very interesting and something we have not considered before,” the source said.

The inquiry, which began last week, must first seek to define the parameters of the markets in which the newly merged group would operate. Then it will determine the impact on these markets of the merged entity.

Sources said that it was difficult to determine whether the preliminary investigation would turn into a formal inquiry. Only 3 per cent of preliminary investigations become formal.

The deal would bring together Google, the world’s biggest search engine, and DoubleClick, operator of a digital marketplace that connects advertising agencies, marketers and website publishers. It has more than 1,500 clients and tracks the progress of the advertisements that it helps to place.

Google has identified advertising as a key area. DoubleClick had been the target of a fierce bidding war between Microsoft and Google. Although Google commands the bulk of the online advertising search market, the addition of DoubleClick’s technology and clients will broaden its stranglehold on internet marketing.

Sir Martin Sorrell, head of WPP, the world’s second-biggest advertising group and an unsuccessful bidder for the company, is one of the most vocal opponents of the deal. It “clearly raised some regulatory issues”, he said. However, he added that it was a “brilliant acquisition” and had been “won fairly”.

“It raises issues as to whether we are happy to let Google have our clients’ data and our own data, which they could use for its own purposes,” said Mr Sorrell, who has since purchased 24/7 Real Media, a rival to DoubleClick.

“Google is a short-term friend and a long-term enemy,” he said, “and probably the shorter term just got a little big shorter and the longer term got a bit closer as a result of the acquisition.”

— Bottom line

$6bn paid by Microsoft for aQuantive this month

$3.1bn paid by Google for DoubleClick

$649m paid by WPP for 24/7 Real Media this month

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