T-Mobile (NASDAQ:TMUS) and Sprint (NYSE:S) are considering the divestiture of some of their assets in order to gain approval from the Justice Department for their proposed merger. The DOJ wants the two companies to make enough concessions that a new fourth wireless carrier could compete in the market. The two companies already agreed to sell off Boost Mobile -- Sprint's prepaid brand -- in order to appease FCC Chairman Ajit Pai.

It's unclear exactly what New T-Mobile -- the resulting company after the merger -- would have to go without, but at the very least it seems it would have to put up some of its wireless spectrum for auction. It might also need to sell off network equipment and customers, as well as offer wholesale network use agreements to the buyer.

But building a customer base and a wireless network requires a lot of cash and a way to reach those customers. Only a few potential buyers make sense. A couple of groups have already come forward offering to submit bids to the government for New T-Mobile's spectrum.

A cluster of cell towers viewed from below.

Image source: Getty Images

Cable industry gets serious about wireless

Comcast (NASDAQ:CMCSA) and Charter (NASDAQ:CHTR) have approached the Justice Department expressing their interest in New T-Mobile's airwaves, according to a report from Bloomberg. Comcast has participated in government spectrum auctions in the past.

The two cable giants have 59.2 million customer relationships between them. They also each operate their own virtual mobile networks, which are growing quickly compared to traditional wireless carriers. The two added a combined 283,000 lines in the first quarter and have 1.7 million customers total.

The two companies combine to cover over 100 million homes and businesses with their broadband internet services, so they'd be able to combine to offer service nationwide for all intents and purposes. They also generate meaningful cash flow from their existing subscriber base, which gives them the resources to build out their own networks while they rely on wholesale and MVNO agreements with existing network operators.

T-Mobile has argued the cable industry and the wireless industry are increasingly competing against one another. Comcast and Charter will face competition from New T-Mobile's home broadband plans as well as T-Mobile's home television plans. Operating their own wireless network might help the two cable operators compete better through bundling and keep their home internet and television subscribers.

Could this be your newest Prime benefit?

Amazon (NASDAQ:AMZN) has also emerged as a potential buyer of New T-Mobile's spectrum assets. The online retailer is reportedly interested in buying both Boost Mobile and the divested spectrum, according to Reuters.

What exactly Amazon would do with its own wireless service is unclear, but the company has made a lot of efforts to increase its touch points with consumers in the recent past. Its hardware business -- which includes Kindle, Fire TV, and Echo devices -- give it a daily presence in consumers lives. Becoming an integral part of a consumer's phone -- one of the most personal devices -- could give its retail or advertising businesses an edge. Amazon notably tried to create a smartphone, but the initial device didn't sell well enough to merit a second iteration.

The company certainly has a large customer base it could sell the service to. Amazon Prime reaches over 100 million Americans, according to a recent estimate from Consumer Intelligence Research Partners. And bundling wireless service with Prime and its music streaming service could be a good way to boost its subscription services revenue and build a substantial customer base.

The acquisition of Boost Mobile could be integral to Amazon, as it would give the company an established customer base and a wholesale agreement with New T-Mobile to use their network for six years while it builds out its own network. If Amazon ends up buying Boost and the other assets New T-Mobile would have to sell, it could make a compelling fourth competitor in wireless.

Anyone else?

Finding a suitable buyer for the divested New T-Mobile assets might need to happen before the DOJ approves the merger. Very few companies have the resources to build a sizable customer base and build out a wireless network on their own. The Comcast-Charter coalition and Amazon are rare companies with the resources to compete. Finding other interested parties might be very difficult, which means New T-Mobile won't have a lot of bidders for its assets (potentially leading to low sales prices).

It looks like there's still a lot more work to do for T-Mobile and Sprint to gain approval for the merger. And getting the merger done may mean selling off assets at a price well below what the company values them. But if it doesn't deteriorate its plans for building out its network, and it doesn't have to sacrifice a significant customer base, New T-Mobile could still realize a lot of value and synergy from combining the two companies.