The sell-off of bankrupt Canadian telecom giant Nortel is reaching its end stages, with a multi-day auction of over 6,000 patents and patent applications belonging to the company selling to a consortium including Apple, Microsoft, RIM, and others for some $4.5 billion in cash. The patents cover a wide range of wireless, 4G, data networking, Internet, voice, optical, and semiconductor technologies.

“We are pleased at the outcome of the auction of this extensive patent portfolio”, said Nortel chief strategy officer George Riedel, in a statement. “The size and dollar value for this transaction is unprecedented, as was the significant interest in the portfolio among major companies around the world.”

The auction took place over several days, and Nortel expects the deal to close during the third quarter of this year. The winning consortium is made up of Apple, EMC, Ericsson, Microsoft, RIM, and Sony. The members have not disclosed their levels of financial participation in the group, although Ericsson has said it put $340 million towards the deal.

The mammoth patent sale follows Google’ acquiring another block of Nortel patents in a $900 million “stalking horse” bid earlier this year that didn’t see any serious competitors. Nortel filed for bankruptcy in early 2009 and has been selling off its considerable assets to pay off creditors. Microsoft paid some $7.5 million for a large range of IPv4 Internet addresses controlled by Nortel.