UPDATE 3-Microsoft CEO willing to walk away from Yahoo bid

(Adds analyst comment in paragraphs 7 and 8, updates shares)

By Ian Simpson

SAN DONATO MILANESE, Italy, April 23 (Reuters) - Microsoft Corp (MSFT.O: Quote, Profile, Research) is prepared to walk away from its $43.6 billion bid for Yahoo Inc (YHOO.O: Quote, Profile, Research) if the two sides can't agree on a price, Chief Executive Steve Ballmer said on Wednesday.

Speaking at a technology conference near Milan, Ballmer said Yahoo's better-than-expected first-quarter results, reported on Tuesday, have not changed Microsoft's view of Yahoo's value.

Microsoft sees Yahoo as a way to compete with arch-rival Google Inc (GOOG.O: Quote, Profile, Research) in the Internet search and advertising arena, but it has limits to what it is willing to pay to get a deal done.

"We're prepared to move forward without a merger with Yahoo," Ballmer said. "We think the best way to move forward quickly (and gain critical mass against Google) is to come together with Yahoo."

"Hopefully that works. But if it doesn't, we go forward," he said. "Time is money. We made (that) clear in the last letter we sent."

In that letter, Ballmer set a Saturday deadline for Yahoo's board to accept a deal with Microsoft or face a lower bid that Microsoft would take directly to Yahoo's shareholders. Yahoo's board of directors has said Microsoft's cash-and-stock offer significantly undervalues the company.

Analysts downplayed the possibility of Microsoft walking away from the deal.