Cox's Bid = The End of Pivot?

More of Sprint?? ventures could be unraveling soon. One sign: Today, cable company Cox announced that it will bid for wireless spectrum in the upcoming 700 Mhz auction.

Cox?? participation in the auction could be construed as a move against Sprint, with whom Cox currently has a wireless joint venture. Cox resells Sprint?? wireless service to its cable customers under a brand called Pivot.

By entering the wireless spectrum auction, Cox could be signaling that it wants to build its own wireless network -- and, essentially, to compete against Sprint.

So it's not just Google and Frontline that threaten incumbents AT&T, Verizon Wireless and Sprint. A company like Cox could pose as big a competitive threat. For Sprint, the threat will be all the greater, as this move means that its Pivot service -- worth tens of million of dollars in investments -- may never get off the ground.