A defiant Microsoft CEO Steve Ballmer said the software giant won't raise its $44.6 billion bid for Internet company Yahoo. "We are prepared to go without a merger," Bloomberg quoted Ballmer in Italy Wednesday.

Microsoft has given Yahoo until Saturday to decide whether it will negotiate. In February, Yahoo rejected Microsoft's original bid as undervaluing the Sunnyvale, Calif.-based company.

Ballmer has said Microsoft will try to vote-out the Yahoo board if a merger is not possible.

Although onlookers have said Yahoo might accept a higher bid, Ballmer said today the software maker has already offered "a lot of money."

Tuesday, Yahoo announced it earned $1.82 billion during the first quarter, a 9 percent increase over the same period in 2007.

Speaking with analysts, Yahoo CEO Jerry Yang said he "will not enter into any transaction that does not recognize the full value of this company," according to the Wall Street Journal.