Yahoo has replied to the three-week ultimatum Microsoft made on Saturday.

In a letter addressed to Microsoft CEO Steve Ballmer, Yahoo said it isn't opposed to an acquisition; it just thinks Microsoft's bid is too low.

"Our board's view of your proposal has not changed," wrote Chairman Roy Bostock and CEO Jerry Yang (via Reuters). "We continue to believe that your proposal is not in the best interests of Yahoo and our stockholders."

Yahoo also said it is on solid financial ground and admonished Microsoft to examine its own corporate physique. "As a result of the decrease in your own stock price, the value of your proposal today is significantly lower than it was when you made your initial proposal," it brazenly argued.

Per the letter Microsoft sent on Saturday, Yahoo has three weeks to act on its buyout bid before Microsoft goes from "unsolicited but friendly" to "unsolicited and hostile." Ballmer also threatened to lower the offer price.

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