After months of lobbying by the US wireless industry, the Federal Communications Commission (FCC) will refund around $2.8bn from spectrum which was auctioned but not delivered.

The down payments represent 85 per cent of the deposits for spectrum licences auctioned by the FCC, which courts later determined the regulator had no right to sell. US operators are still pushing for a full refund.

Verizon Wireless, in which Vodafone has a 45 per cent stake, and which was the biggest bidder in the January 2001 auctions, maintains that the FCC must rule the auction void and release the winning bidders from their commitments as well as return the down payments in full.

Verizon made a $1.7bn down payment and has already filed with the US Court of Appeals to force the agency to return the money in full.

Even after this refund, the FCC still holds around $260m of Verizon's deposit, and the telco said that it has lost at least another $115m in unpaid interest on the sum.

The FCC is challenging a bankruptcy court ruling that the licences should not have been auctioned as they still belonged to two bankrupt companies, NextWave and Urban Comm-North Carolina.

Both had won licences at auction in 1996 but defaulted on their payments to the FCC.

In handing back the bulk of the deposits the regulator said that, if it wins its challenge to that judgement, it will require "winning bidders to pay the full amount of their winning bids".

Analysts feel certain that Verizon and the other US operators with winning bids will get their way.

"Verizon will not stop until it gets all its money back, and the FCC will not win in the appeals court," said Christine Loredo, a senior analyst at the Strategis Group.