Sprint (S) operates in a strange place where it has to act as an independent company while working to make sure it's ready to merge with T-Mobile (TMUS 0.02%). That merger still requires federal approval, and while the OK is expected, it's not a sure thing.

That leaves Sprint in a state of limbo. It has to operate in its own long-term interests, but it can't make investments that won't make sense if the deal gets approved.

It's a tough place to be, because should the deal be denied, Sprint will find itself needing a partner but lacking an obvious choice. Yes, one of the cable companies may be willing to buy the company at a discount, but that's not something management or shareholders want to see happen.

With a successful T-Mobile merger, Sprint becomes part of a growing company that will have the resources to take on AT&T (T -1.21%) and Verizon (VZ -4.67%). That would make Sprint shareholders owners of the new T-Mobile -- a decidedly better place to be than where they are now.

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If the deal is approved

The merger values Sprint at roughly the $6.50 per share it was trading at when the deal was announced. That number was likely a disappointment to shareholders, but there is an upside: T-Mobile stock has generally been climbing upward since 2015. In fact, you can argue that the share price would be higher now if the uncertainty over the merger wasn't holding it back.

T-Mobile has added more than 1 million customers for 22 straight quarters. If it adds Sprint, it will have a customer base that's similar to the ones served by AT&T and Verizon. That should allow the combined company to roll out 5G faster without taxing its resources as much. It would also give the company a larger base to market T-Mobile's upcoming television service to.

CEO John Legere, who will run the combined company, has proven that he can take on AT&T and Verizon. Giving him more assets to use in that battle should increase value for T-Mobile (and former Sprint) shareholders. That makes the successfully merged company a potential millionaire-maker stock. Legere won't knock out either of his big rivals overnight, but he has shown he can chip away at their customer bases, making meaningful progress every quarter.

John Legere and Marcello Claure.

Legere (left) and Sprint chairman Marcello Claure had a joint media event when the merger was announced. Image source: T-Mobile.

If the deal isn't approved

Without T-Mobile, Sprint goes back to being the No. 4 wireless carrier, which has only been able to add customers by offering heavy, unsustainable discounts. In this scenario, the company would struggle to compete with its three bigger rivals and would almost certainly need a partner to be able to build out a 5G network.

This version of Sprint would struggle to stay in business, and its stock price would suffer. The company has already shown that it can barely compete in the current environment, and it will fall further behind as next-generation technology gets rolled out.

If the T-Mobile deal gets shot down, Sprint will talk with the major cable companies, but both Comcast and Charter have already passed on deals with the carrier. It's possible that either might be interested, but it would take both sides really wanting it to drive the price up.

That's very unlikely. Sprint without T-Mobile is not a growth proposition, so the best hope for owning shares in a potential millionaire-maker stock lies with the federal regulators who will make a decision on this deal.

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