Microsoft has teamed up with private equity firm Silver Lake Partners and the Canada Pension Plan Investment Board for the offer, but has not yet decided whether to go through with it, the Journal said, citing unnamed sources.

The newspaper said at least nine private equity firms are eyeing Yahoo! and its global audience of 700 million monthly visitors to the company's various websites, including Yahoo! News, Yahoo! Finance and Yahoo! Sports.

It added that under the Microsoft deal, the buyers would spin off Yahoo!'s Asia assets after a takeover.

Yahoo! shares surged more than 10 percent earlier this month on speculation that Microsoft would lodge a new bid for the web giant more than three years after being spurned.

Microsoft was publicly humiliated in 2008 when Yahoo! co-founder Jerry Yang rejected a generous bid for the company at $33 a share, a valuation of more than $47 billion.

At the time a frustrated Microsoft chief Steve Ballmer emphatically said he was through with Yahoo! acquisition talks.

Meanwhile many Yahoo! shareholders blasted the company for spurning Microsoft, contributing to Yang's decision to step aside as chief executive.

The Journal said some private equity firms expect a deal for Yahoo! can now be done for around $16-18 per share, valuing the company at $20 billion to $22.7 billion.