The US Federal Trade Commission (FTC) has postponed a decision on whether to challenge Google over its planned $750m acquisition of AdMob.
The FTC has been granted a two-week extension to question Google's competitors and advertisers in a review of the acquisition, according to the San Francisco Chronicle.
The FTC has prioritised instead an investigation into the effects of Apple buying Quattro Wireless in January to compete with Google.
The FTC is believed to be concerned about the conditions Apple is imposing on software developers and advertisers for its iAd advertising platform.
Apple announced iAd in April to help software developers generate revenue from the applications they create for Apple's iPhone, iPod Touch and iPad.
Developers can choose whether or not to include ads in their applications, but if they do, they are set to get 60% of the revenue, with the remainder going to Apple, after the system goes live in June.
Apple is expected charge up to $1m for displaying adverts using the iAd system and even more for advertisers who want to be among the first to use the system.