AT&T facing stiff competition in hunt for nationwide 5G spectrum.

An all-out bidding war for Straight Path broke out on Monday, after the unnamed suitor vying with AT&T to land the 5G spectrum holder upped its offer to $3.1 billion (€2.84 billion).

It is the second time in less than a week that the anonymous multinational telco has upped the ante. It initially topped AT&T’s $95.63 per share bid with an offer in April of $104.64. Then, last Wednesday, it raised that offer to $135.96. Its latest bid is worth $184.00 per share.

Earlier in April, AT&T agreed to acquire Straight Path earlier in April in an all-stock deal worth $1.6 billion, including liabilities and outstanding settlement payments owed by Straight Path to the Federal Communications Commission (FCC).

The rival offer is also an all-stock affair; it expires on 10 May. While the identity of the bidder is under wraps, recent reports claimed that Verizon was considering entering the race for Straight Path.

As before, Straight Path on Monday said it considers this latest offer superior to AT&T’s. It has given AT&T three working days to meet or exceed the new bid.

Straight Path reiterated that as things stand, its board has not changed its recommendation in support of the AT&T transaction. Were that to happen, Straight Path would have to pay AT&T a $38 million break-up fee.

Whoever wins will gain an enviable portfolio of nationwide millimetre wave (mmWave) spectrum, which is expected to become vitally important when it comes to delivering bandwidth-hungry 5G services.

Virginia-based Straight Path holds 735 licences for 39-GHz spectrum plus 133 licences for 28-GHz spectrum. These licences cover the entire U.S., including the top 40 markets.

In November 2015, an anonymous source accused Straight Path of misleading the FCC in order to renew its 39-GHz licences. According to the source and the investigation that followed, Straight Path deployed network equipment solely to convince the FCC that it was fulfilling its obligation to put its spectrum to use. Once the renewals were granted, the equipment was taken down again.

Under a settlement with the FCC reached this January, Straight Path agreed to pay a $15 million fine and return 196 of its 39-GHz licences to the regulator. It also agreed to sell its remaining frequencies within 12 months to avoid a further $85 million fine.