Microsoft co-founder Paul Allen will bid at an auction for wireless spectrum that's becoming available in late January, alongside industry giants such as AT&T, Google, and others. The billionaire businessman will make the bid through a subsidiary of his Vulcan Capital investment firm.

Mr. Allen's entry into the auction came as a surprise, though his company, Vulcan Spectrum, already owns a swath of the 700-megahertz band that the Federal Communications Commission (FCC) will auction next month. Vulcan Spectrum acquired 24 licenses in the 700-megahertz range in 2003, all of which apply to the Seattle, Washington and Portland, Oregon areas.

Allen 's plans for the auctioned spectrum remain a mystery. Some theorize that he's simply purchasing it now in order to resell it at a profit later. But such a move runs counter to the FCC's plans: The Commission is requiring the purchaser to build out the network and put the spectrum to use. One condition of the sale is that its owner allows customers to run different devices and software on the wireless network created in the spectrum. That condition was prompted by Internet search and advertising giant Google, which will also participate in the bidding.

Mr. Allen co-founded Microsoft with Bill Gates in 1975, where he helped co-develop the company's first products, including a version of BASIC for the first personal computer, the MITS Altair. He resigned from Microsoft in 1983 after being diagnosed with Hodgkin's disease, but successfully treated the disease and went on to create a number of companies over the years, including Asymetrix and Vulcan Ventures. Allen funded the SpaceShipOne private spacecraft project and owns professional sports teams like the Portland Trailblazers (basketball) and the Seattle Seahawks (football).