Count Microsoft among the potential buyers if Yahoo opts to go on the auction block.
The tech company, which tried to buy Yahoo for $44 billion in 2008, has signed a confidentiality agreement, allowing it to take a closer look at the portal's books, according to a report in Reuters. The publication cites "a source familiar with the matter."
A spokesperson for Microsoft said the company did not comment on "rumors and speculation.”
Yahoo did not immediately respond to requests for comment.
With its stock in the doldrums and its push into original content yet to pay off, Yahoo's board has been flirting with the idea of selling the company since firing Carol Bartz as CEO last September.
The company has also weighed other scenarios, including divesting its more lucrative Asian assets like Alibaba and Yahoo Japan, investors and analysts have also told TheWrap.
Microsoft is not alone in the hunt this time. Private equity firms KKR and TPG Capital have also signed confidentiality agreements, according to Reuters.
Yahoo's stock slipped .47 percent to $14.90 in after hours trading.