Microsoft went public Friday with a $44.6 billion cash-and-stock bid to acquire Yahoo.
In its response, Yahoo called the Microsoft bid "unsolicited" but did not reject it.
Microsoft's offer, which was contained in the letter to Yahoo's board, amounts to $31 a share and represents a 62 percent premium over Yahoo's closing price on Thursday. Microsoft said it will offer shareholders the option of cash or stock.
"We have great respect for Yahoo, and together, we can offer an increasingly exciting set of solutions for consumers, publishers, and advertisers while becoming better positioned to compete in the online-services market," Microsoft CEO Steve Ballmer said in a statement.
Further updates and analysis to come.