Complex sentence: Mattel purchased the company in 1999 for $3.8 billion from the Canadian Entrepreneur Kevin O'Leary, renaming it "Mattel Interactive", in what has been called one of the worst acquisitions in corporate history.
Split into simpler sentences: Mattel purchased the company in 1999 for $3.8 billion from the Canadian Entrepreneur Kevin O'Leary. It has been called one of the worst acquisitions in corporate history.