According to numerous sources, Microsoft execs have been meeting with private equity firms mulling over bids to buy Yahoo and telling investors the company might be willing to lend significant financing to their efforts.

As most know, Yahoo has said it is for sale. Some question the company’s commitment to the process, given how glacial it has been, which many attribute to CEO Marissa Mayer’s antipathy toward it, favoring her own turnaround efforts instead.

Today, activist shareholder Starboard Value said as much, mounting a long-expected proxy challenge to Yahoo and naming its own slate of directors to replace current ones.

Starboard’s Jeff Smith noted that the new board was needed to bring “credibility to a process that has been publicly criticized repeatedly for being too slow, fraught with conflicts of interest and very difficult for highly qualified and motivated strategic and financial buyers to access much-needed diligence information.”

Every single possible buyer I have spoken to this week agreed in spades, with many calling the Yahoo sale effort a farce. The current Yahoo board has said it is not, but the credibility of the current Yahoo board is — let’s be honest — under some much-deserved scrutiny.

In any case, adding Microsoft into the mix does give this process some seriousness. Microsoft’s partnerships and acquisition strategy head Peggy Johnson is part of the effort, as well as others at Microsoft, sources said (you can hear my Re/code Decode podcast interview with her from last fall below).

To be clear, the software giant has made no commitments so far to any investors, and any discussions now are exploratory. But sources said that the reason for providing financing would be because Microsoft wants to ensure that if Yahoo is sold, whoever buys it will be a good partner going forward. That makes sense, since Microsoft has close search and advertising ties with Yahoo, part of a longtime partnership.

That deal was struck after Microsoft made a hostile bid to buy Yahoo in 2008. At the time, former CEO Steve Ballmer offered $31 a share; at that time it was worth about $45 billion.

Ultimately, the effort was unsuccessful, but it was ugly by more friendly tech standards.

Since then, the companies have had a more cooperative relationship, although there was some recent tension when Mayer tried to get out of parts of the current search deal via a lawsuit that failed. She ended up renegotiating the deal a year ago on more favorable terms for Yahoo and later signed another search deal with Google, too.

Preserving its current status is important to Microsoft, said sources, which is why it has been mulling the financing of possible Yahoo buyers, who will have to come up with billions of dollars in cash to be competitive. “If Microsoft put in a billion, it would cost them almost nothing,” said one investor who had spoken to the company. “It’s a minor thing and it buys them a lot.”

Yahoo’s market cap is currently $32.5 billion, but that includes its stakes in its Asian assets. After the spin-off of its Alibaba Group assets and minus-ing out its shares of Yahoo Japan, most peg the price of its core business at $6 billion to $8 billion.

But sources close to Yahoo’s board said it wants $10 billion in a sale. (By way of comparison, I want a pretty pony from Microsoft comms head Frank Shaw and have a better chance of getting it.)

Sources within Microsoft said the company had no interest in making a more significant bid, but others do. This week, sources said, Yahoo began engaging with “strategic” bidders that include AT&T, Verizon and Comcast. PE and other investment firms will come next, the sources said, and those interested include Advent International, Vista Equity Partners (this one interests me the most), TPG, KKR and others.

A Microsoft spokesman who will not buy me a pony anytime soon declined to comment.