Federal antitrust authorities have approved Nokia Siemens Networks’ $650 million bid for Nortel’s wireless assets, according to the Federal Trade Commission.  

The FTC, which assesses mergers for potential antitrust violations along with the Justice Department, named the deal on a list of approved mergers issued on Tuesday.

Nokia Siemens acted as the "stalking horse" for the bankrupt infrastructure company’s assets, setting the floor for bidding by making the first bid . No other bids have yet been put forward for the assets, but Nortel creditor MatlinPatterson argues that Nokia Siemens’ bid is too low and is working to submit a competing proposal that would keep the bankrupt infrastructure company intact.

In a statement, the private equity firm argued that it wanted to try and retain Nortel’s value “rather than merely accepting a ‘fire sale’ of its core asset followed by the wholesale liquidation of the remaining businesses.”

Nokia Siemens spokeswoman Chantal Boeckman declined to comment on the firm’s characterization of the deal as a “fire sale” but reiterated that the company believed its bid was the “best possible outcome for Nortel, its customers and employees.”

Nortel spokeswoman Karen Monaghan also declined to comment pending the formal acceptance of MatlinPatterson’s bid.

The firm, which specializes in restructuring financially troubled companies, plans to outbid Nokia Siemens and restructure Nortel around its wireless assets. It has until the July 21 deadline imposed by the U.S. Bankruptcy Court to submit its proposal. The auction for Nortel’s assets has been set for July 24, and the bankruptcy court hearing is scheduled for July 28.

Securing Nortel’s CDMA assets and Long Term Evolution research unit would help Nokia Siemens gain a strategic foothold in the North American market. The assets drove profits at Nortel, and although the segment’s sales had been in decline, it still managed to earn about $700 million a year.

If the deal goes through, Nokia Siemens would likely recoup its $650 million investment within one to two years.