Google

U.S. regulators are seeking sworn declarations from Google Inc. competitors and advertisers as part of their probe of the Internet company’s bid to buy AdMob Inc., indicating the government may challenge the deal, said people with direct knowledge of the matter.

The Federal Trade Commission is investigating whether Google’s proposed purchase of AdMob would reduce competition in the market for Internet advertising on mobile phones. At least two companies are being asked to sign statements, said the people, who declined to be identified because the probe isn’t being conducted in public.

The declarations put on paper information that Google rivals gave the FTC in its investigation of the $750 million purchase of AdMob, announced in November. AdMob sells ads that appear on Web pages and applications on mobile phones. The agency is assessing whether the purchase would let Google parlay its dominance in Internet searches on computers to phones.

Agency officials typically collect declarations “when they think there is some significant chance” the agency will ask a court to block a merger, or seek to modify a deal, said Stephen Calkins, a former general counsel at the FTC who is now a professor of law at Wayne State University’s law school in Detroit. Even so, it’s not uncommon for the agency to collect affidavits and then not litigate, he said.