By MICHAEL LIEDTKE, AP Business Writer

SAN FRANCISCO - Yahoo Inc. spurned Microsoft Corp.'s $44.6 billion takeover bid as inadequate Monday, betting that it can elicit a higher offer from the world's largest software maker or find another way to deliver a comparable payoff to its shareholders.

The rebuff by the slumping Internet pioneer had been widely anticipated after word of Yahoo's intention was leaked during the weekend.

In its formal response, Yahoo said its board had concluded Microsoft's unsolicited offer "substantially undervalues" the Sunnyvale-based company.

Yahoo indicated it could be drawn to the negotiating table if Microsoft ups the ante, without mentioning the price it has in mind.

"The board of directors is continually evaluating all of its strategic options in the context of the rapidly evolving industry environment and we remain committed to pursuing initiatives that maximize value for all stockholders," Yahoo said in a statement.

Investors appeared confident that Microsoft wants Yahoo badly enough to raise the stakes. Yahoo shares rose 65 cents to $29.85 in Monday's early morning trading while Microsoft shares fell 58 cents to $27.98.

Yahoo's stock price had dropped by more than 40 percent in the three months leading to Microsoft's bid, valued at $31 per share when it was announced Feb. 1. The offer was 62 percent above Yahoo's market value at the time.

Many analysts believe Redmond, Wash.-based Microsoft will eventually raise its bid to $35 to $40 per share, sweetening the pot by $5 billion to $12 billion in an effort to negotiate an amicable sale.

But a higher bid could hurt Microsoft's own stock price, which has been slipping amid concerns that a Yahoo takeover could be more trouble than its worth. Microsoft's market value has plunged by more than $40 billion, or 14 percent, since the bid was made public.

If it doesn't want to pay more money, Microsoft could take its original bid directly to Yahoo's shareholders. If it pursues that risky route, Microsoft might have to antagonize Yahoo by trying to oust the 10-member board that rejected the original offer.

Microsoft representatives didn't immediately respond to requests for comment Monday morning.

Although its profits have been dwindling during the past two years, Yahoo still possesses one of the Internet's biggest audiences and most valuable franchises. Microsoft believes it can build on those assets to become a more formidable competitor to Google Inc., which now holds a commanding lead in the lucrative online search and advertising markets.

Yahoo has reportedly been exploring an advertising partnership with Google as one way to boost its profits and remain independent. The company also has been looking for other suitors that might be interested in countering Microsoft's bid, but so far no one has stepped forward.

By rejecting Microsoft's initial offer, Yahoo's board is running the risk that the company's stock will plunge below $20 per share again if its suitor decides to walk away.

That scenario would probably unleash a flood of shareholder lawsuits, intensifying the pressure on Yahoo's management team to deliver on a long-awaited turnaround that has been in the works for the past 18 months.