Following Softbank's October agreement to purchase a 70% stake, the Sprint CEO has more in mind than the recently announced $100 million purchase of additional shares of wireless broadband provider Clearwire Corp.

The picture will likely begin to clear Thursday when the two companies release quarterly earnings. Sprint may not outline its intentions in any detail. Clearwire, however, should provide information on its cash burn, its success at attracting customers and its ability to remain in business without a significant infusion.

Hesse has said that a healthy Clearwire is in the best interest of Sprint, which is the largest shareholder and largest customer of the Bellevue, Wash., wireless upstart.

"Clearwire is going to need some form of funding before the end of 2013," said Shing Yin of Guggenheim Securities LLC. "Right about now is when they need to start thinking about how to get that funding."

In the first phase of Softbank's capital infusion, Sprint said Monday it has closed the sale of a $3.1 billion note that will convert to a 19.65% stake. The Japanese telecom will provide about $5 billion in additional capital next year, and will pay $12 billion to Sprint shareholders.

"I'd say the amount of funding they need is at least a billion or more," Yin said of Clearwire.

Exactly how much depends upon the company's aspirations, he added. In the first phase of a long-term evolution, or LTE, wireless broadband deployment, Clearwire plans to overlay 5,000 of its sites with the new technology. Ultimately, it will add LTE to up to 8,000 of its sites.

Even a modestly sized carrier such as MetroPCS Communications Inc. has about 18,000 sites.

Yin suggested that Clearwire probably needs 40,000 sites for a national network, which would require "multiple billions" in capital, possibly $3 billion to $5 billion.

Another variable is how Sprint could structure a deal. Sprint could simply take a larger equity stake. Yin noted that the company could take other approaches, such as participating in a refinancing.

Clearwire has about $4.3 billion in long-term debt, and about $1.2 billion in cash.

Starting December 2012, Clearwire can call $2.95 billion of the debt, in the form of senior secured notes paying 12% interest.

Sprint could provide Clearwire a loan to refinance the obligations, presumably at a significantly lower rate than the carrier is paying.

Sprint disclosed earlier in October that it is paying Clearwire founder Craig McCaw's Eagle River Holdings LLC $100 million for its stake in Clearwire. The price breaks down to $2 per class A share and $13.99 per class B share, for an average cost of $2.97 per share. The deal will put Sprint's voting stake in Clearwire to 50.4%, though it has a larger economic position.

Fitch Ratings Inc. analyst Bill Densmore described the relationship as "an evolutionary process" between Sprint and Clearwire.

"We don't know when the endgame occurs," he said.

Sprint has had a majority voting position before, Densmore observed, but took steps to reduce its stake to avoid the danger of a cross-default if Clearwire ran into debt problems. The carrier could do so again if there are concerns about the carrier's viability.

Fitch estimates that Clearwire burns $700 million to $800 million of cash a year.

"Given their annual cash burn, they could be a going-concern risk late this year or in early 2013 without another cash infusion," Densmore added.

In a Wednesday note, Jonathan Schildkraut of Evercore Partners suggested that Sprint will likely buy its lagging wholesale partner. The motivation is Clearwire's spectrum portfolio, which includes 160 MHz in the top 100 markets and is critical to Sprint's goal of continuing its unlimited data service.

Schildkraut suggested that the unlimited package will become a bigger selling point in the coming years, as Sprint tries to win share from Verizon Wireless and AT&T Inc.

The Eagle River deal may put a floor of $2 per share on Clearwire stock in a Sprint takeover scenario, Schildkraut wrote, because of provisions that protect minority shareholders.

Shares of Clearwire traded down 2 cents, or about 1%, to $1.89 per share Wednesday afternoon, more than a dime below the floor that the Eagle River deal implies.

There is the prospect that another party could provide Clearwire with capital. As Sprint's stake grows, however, there is less incentive for another telecom to get involved.

There may be an inverse relationship between Clearwire's operating strength and Sprint's motivation to make a deal. If its health is a concern, as Hesse suggests, capital is the most reliable prescription.

"The weaker Clearwire is and the more desperate it becomes for cash, the more likely it is that a deal happens," said Gimme Credit LLC analyst Dave Novosel.

There will be more data on Clearwire's relative strength or weakness on Thursday.