The Federal Communications Commission’s (FCC) latest spectrum auction kicked-off, covering 8,017 county-based overlay licences in the 2.5GHz band which analysts predict will primarily be of interest to T-Mobile US.

Auction 108 covers blocks in 49.5MHz, 50.5MHz and 17.5MHz in each county, with licences mostly in rural areas.

The 2.5GHz auction is using a clock-1 format, which allows only a single frequency-specific licence in a category in a county rather than offering multiple generic blocks across a broader geographic area.

FCC chair Jessica Rosenworcel stated Auction 108 was a unique opportunity to fill 5G coverage gaps, but analysts largely view T-Mobile as the likely winner of a large number of the licences, enabling it to close holes in its current portfolio.

Rivals AT&T, Verizon and Dish Network are also among potential bidders, though Phil Burnett, communications services analyst with New Street Research, previously noted it would cost Verizon billions to add 2.5GHz radios to its towers, while AT&T and Dish Network have a significant amount of debt from previous spectrum auctions.

Blair Levin, policy adviser to the research company, previously estimated Auction 108 could raise between $1.5 billion and $5.5 billion.

The FCC’s authority to conduct spectrum auctions is set to expire on 30 September, but legislation is in the works to extend it to 21 March 2024 along with making additional spectrum in the 3.1GHz and 3.4GHz range available for 5G.

Levin told Mobile World Live there are differing views on how to expand the FCC’s authority, which “likely leads to a short-term, narrow solution”.