(Reuters) - Straight Path Communications Inc STRP.A said on Monday an unnamed telecommunications company had raised its offer to buy the wireless spectrum holder, in the latest move in a bidding war with AT&T Inc T.N.

The unnamed company is Verizon Communications Inc VZ.N, sources familiar with the matter told Reuters.

The all-stock offer of $184 per share represents an enterprise value of about $3.1 billion, Straight Path said.

The offer reflects an equity value of about $2.3 billion, according to Reuters calculations.

That tops AT&T Inc's T.N offer of $95.63 per share or $1.25 billion, which was announced last month.

Straight Path’s shares jumped nearly 26.3 percent to $204 in premarket trading on Monday. Shares of Verizon and AT&T were largely unchanged.

Straight Path, which holds a large trove of 28 GHz and 39 GHz millimeter wave spectrum used in mobile communications, would give a new owner an advantage in 5G development.

Verizon and AT&T are seeking to gain an edge in the race to develop a fifth-generation network (5G) that would offer faster downloads and boost internet-reliant products such as self-driving cars.

Straight Path also reiterated that the unnamed bidder would cover the termination fee of $38 million that Straight Path would be required to pay AT&T if Straight Path picked another buyer.

The unnamed company had last week offered $135.96 per share for Straight Path and Monday’s bid tops that offer, Straight Path said.