Oracle is to buy computer hardware and software maker Sun Microsystems for $US7.4 billion.
The business software manufacturer will pay $US9.50 in cash per share for Sun, which is a premium of 42% over Sun's closing stock price on Friday.
A statement issued on Monday said the sale is subject to regulatory approval and should be completed this summer.
Sun was previously in talks with IBM, which abandoned the bid last month.
The deal will give Oracle ownership of the Java programming language, which powers more than one billion devices - including mobile phones, electronic games and personal computers.
Oracle said the takeover of Sun would boost its profits by more than $US1.5 billion in the first year and by $US2 billion in the second.
However, Sun made a loss of $US1.9 billion over the past 12 months, despite sales totalling $US13.3 billion.