Computer chipmaker Intel has been fined a record 1.06bn euros ($1.45bn; £948m) by the European Commission for anti-competitive practices.
It dwarfs the 497m euro fine levied on Microsoft in 2004 for abusing its dominant market position.
The Commission found that between 2002 and 2007, Intel had paid manufacturers and a retailer to favour its chips over those of Advanced Micro Devices (AMD).
Intel has announced that it will appeal against the verdict.
Intel's senior vice president Bruce Sewell told BBC Five Live that Intel contested the findings and was seeking a chance to "clear our name and exonerate the company."
He denied "categorically" that it had paid manufacturers to favour its products over those of rivals.
"We would never pay for any kind of obligation," Mr Sewell said. "We provide incentives to customers to buy our products."
He added that there had been no harm to customers and that prices in the microprocessor market had fallen sharply in recent years.
The fine was welcomed by AMD, which had lodged complaints in 2000, 2003 and 2006.
"The EU decision will shift the power from an abusive monopolist to computer makers, retailers and above all PC consumers," said Giuliano Meroni, AMD's European president.
