The Department of Justice on Tuesday approved the pending merger of Google and Motorola Mobility, as well as the purchase of Nortel patents by Apple, Microsoft, and Research in Motion.

The Department of Justice on Tuesday approved the pending merger of Google and Motorola Mobility, finding it unlikely that the two companies will use their patent holdings to give themselves a competitive advantage.

Similarly, the agency also approved the purchase of Nortel patents by Apple, Microsoft, and Research in Motion.

"After a thorough review of the proposed transactions, the Antitrust Division has determined that each acquisition is unlikely to substantially lessen competition and has closed these three investigations," the DOJ said in a statement.

Of particular interest, the DOJ said, was whether the deals would allow the tech giants to go after rivals for patent infringement. Instead, the companies have agreed to license their patents on fair, reasonable and non-discriminatory (FRAND) terms.

The DOJ said Apple and Microsoft made "clear commitments" to license patents on a FRAND basis, though "Google's commitments were more ambiguous and do not provide the same direct confirmation" of its licensing plans.

"The evidence shows that Motorola Mobility has had a long and aggressive history of seeking to capitalize on its intellectual property and has been engaged in extended disputes with Apple, Microsoft and others," the DOJ found. "As Google's acquisition of Motorola Mobility is unlikely to materially alter that policy, the division concluded that transferring ownership of the patents would not substantially alter current market dynamics."

In fact, Google purchased Motorola Mobility in part to bolster its patent portfolio after it the Nortel patents. Prior to the Motorola acquisition, Google accused Apple, Microsoft, and other tech giants of with its coordinated patent purchases and pledged to "intensely" defend its mobile OS through patent purchases of its own.

With its of Motorola Mobility in late August, Google said it would "supercharge" Android.

The DOJ said it "will not hesitate to take appropriate enforcement action" against companies that abuse their rights.

The DOJ approval, meanwhile, comes one day after the of Google and Motorola Mobility, finding that the deal would not significantly alter the market as it relates to mobile operating systems and patents.

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