In a statement Yahoo! said "our board's view of your proposal has not changed."

Microsoft offered $31 per share in January, roughly $45 billion. Within the week, Yahoo!'s board rejected the bid.

Microsoft's Chief Executive Officer Steven Ballmer provoked the new rebuttal by sending a letter to Yahoo!'s board, threatening to lower the offer per share, which has already dropped to $29 due to a decrease in Microsoft's shares, The New York Times reported Monday..

Ballmer has also threatened to begin a proxy battle by seeking to replace Yahoo! board members.

Offers from each company have met twice since the offer was first made, but no formal negotiations have taken place, the Times reported.

An expert in corporate law, Michel Klausner, said, "Microsoft still prefers a negotiated deal to a proxy fight," but understand that it can lower the price, because Yahoo! has not found any alternative.

Others say Yahoo! shareholders would eventually approve a deal if the company does not find any better deals.