SAN FRANCISCO — Yahoo Inc. spurned Microsoft Corp.’s $44.6 billion takeover bid as inadequate today without explaining how its management will match the payoff that the slumping Internet icon’s shareholders would have received had the unsolicited offer been accepted.

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

By rejecting Microsoft, Yahoo’s board appears to betting that it will be able to extract a higher offer from the world’s largest software maker or its management team will finally be able to deliver on its repeated promises of a turnaround that has been in the works for the past 18 months.

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.

Alternatively, Microsoft could take its original bid directly to Yahoo’s shareholders. If it goes down that route, Microsoft might have to antagonize Yahoo by trying to oust the 10-member board the rejected the original offer.

Microsoft representatives didn’t immediately respond to requests for comment this morning.

Yahoo shares rose 62 cents, or 2 percent, to $29.82 in early trading Monday while Microsoft shares lost 24 cents to $28.32.