The FCC’s mid-band spectrum auction has concluded its initial phase, and the bidding reveals carriers are all-in on mid-band.

Throughout much of the world, mid-band spectrum has been the cornerstone of 5G rollouts. In the US, however, the Big Three carriers have focused on low and high-band. The only exception is T-Mobile, which inherited a wealth of mid-band spectrum from its acquisition of Sprint, and immediately began deploying it.

As Forbes’ Bob O’Donnell points out, all three carriers have spent big at the FCC auction, speaking volumes about their view of the 5G market. Verizon has spent approximately $30 billion, AT&T has spent $20 billion and T-Mobile has spent $10 billion.

As O’Donnell points out, regardless of how much each carrier has been touting their low-band network for its coverage, or their high-band mmWave network for its speed, mid-band is clearly where it’s at. Mid-band is widely seen as the sweet spot for 5G, offering a good balance of coverage and speed. In fact, T-Mobile has even demonstrated speeds of 1 Gps using its current mid-band spectrum. At the same time, mid-band offers far better coverage than the couple of hundred meters that mmWave offers.

Another benefit of US carriers rallying around mid-band is that it helps phone and cellphone radio makers consolidate the number of frequencies they have to support.

Either way, the investment is good news for customers.