Microsoft said on Sunday it proposed an alternative deal to Yahoo rather than a full acquisition. Microsoft's statement on Sunday said it was "considering and has raised with Yahoo an alternative that would involve a transaction with Yahoo but not an acquisition of all of Yahoo." It did not clarify what that alternative might be.

The New York Times reported that Microsoft and Yahoo may form a partnership or joint venture for search-related advertising to take on Google, which dominates the search market with a share significantly larger than a combined Yahoo and Microsoft.

Yahoo continues to talk with Google about a search advertising partnership.

Microsoft emphasized it was not proposing to make a new bid to buy all of Yahoo, after recently being rebuffed, but could reconsider.

Yahoo replied later on Sunday that it continued to consider a number of strategic alternatives and was "open to pursuing any transaction which is in the best interest of our stockholders."

The company's board will "evaluate each of our alternatives, including any Microsoft proposal, consistent with its fiduciary duties, with a focus on maximizing stockholder value," Yahoo said in a statement.

It added it had confirmed with Microsoft that it was not interested in "pursuing an acquisition of all of Yahoo at this time."

Last week, financier Icahn launched a proxy campaign on Thursday to replace Yahoo's board with directors who would reopen talks with Microsoft, saying Yahoo had acted irrationally in refusing the giant software company's $47.5 billion bid.

Microsoft walked away from its pursuit of Yahoo two weeks ago after three months of negotiations when Yahoo's board rejected Microsoft's sweetened offer of $33 a share, saying the company was worth at least $37 a share.