The Federal Trade Commission (FTC) has closed its investigation into the $750 million Google/AdMob buyout and given a green light to the deal. The reason is simple: Apple, Apple, and more Apple.

In its official statement (PDF), the FTC mentions "Apple" 10 times in a page and half, all because of Apple's own decision to launch a mobile ad network called iAd.

"The Commission reached this decision based on important developments in the mobile advertising marketplace, particularly actions by Apple that should mitigate the anticompetitive effects of Google’s AdMob acquisition," said the FTC. The vote in favor of closing the investigation was 5-0.

The Commission had been concerned over Google's dominance in online ads; purchasing one of the big iPhone ad players would have extended that dominance into the mobile space. Apple's announcement changes the game, though: "As a result of Apple’s entry, AdMob’s success to date on the iPhone platform is unlikely to be an accurate predictor of AdMob’s competitive significance going forward, whether AdMob is owned by Google or not. This is particularly important given that AdMob’s revenue and market share are derived largely from the iPhone platform."

Google, which has of late taken to publicly calling for quick action on the deal and vowed to fight a negative ruling, was predictably thrilled. "The decision is great news for the mobile advertising ecosystem as a whole," said the company in a statement today. "As mobile phone usage increases, growth in mobile advertising is only going to accelerate. This benefits mobile developers and publishers who will get better advertising solutions, marketers who will find new ways to reach consumers, and users who will get better ads and more free content."

Over at AdMob, CEO Omar Hamoui said that he was "extremely pleased with today’s decision from the Federal Trade Commission to clear Google’s acquisition of AdMob. Over the past six months we've received a great deal of support from across the mobile industry—and we deeply appreciate it. Our focus is now on working with the team at Google to quickly close the deal."