Google on Friday revealed that it will compete to buy wireless spectrum in a forthcoming US auction, carrying through on a promise that could give it a big stake in the US mobile industry.

The company hinted that it is likely to offer at least $4.6bn for the most valuable piece of spectrum on offer. However, most observers believe that other recent events have reduced the incentive for it to bid more aggressively, and that Verizon Wireless remains the most likely eventual buyer.