A U.S. federal jury found that Microsoft infringed audio patents held by Alcatel-Lucent and should pay $1.52 billion in damages, the No. 1 software maker said on Thursday.
Microsoft said it plans to first ask the trial judge to knock down the ruling and will appeal if necessary. It said the verdict is unsupported by the law and that it had already licensed the technology in question from Germany's Fraunhofer.
Alcatel-Lucent had accused the world's biggest software maker of infringing patents related to standards used for playing MP3 digital music files.
Analysts claim the decision means Alcatel-Lucent may seek payments from providers of software and hardware that support MP3 files, including Apple 's iPod and iTunes.
The $1.52 billion awarded was based on 0.5 percent of the price of personal computers sold since around mid-2003, Tom Burt, Microsoft's deputy general counsel, said.
Microsoft said the award could be roughly halved because it related to overseas sales depending on the outcome of a patent case being heard by the U.S. Supreme Court, which coincidentally also involves Microsoft.
The high court is considering whether companies should be held liable for damages in U.S. patent cases for infringing software distributed overseas.
Microsoft said it has already licensed the MP3 technology in question from German research organization Fraunhofer Gesellschaft for $16 million.
"We are concerned that this decision opens the door for Alcatel-Lucent to pursue action against hundreds of other companies who purchased the rights to use MP3 technology from Fraunhofer," Burt said. Computer, cell phone and MP3 player makers may be affected as well as software suppliers, he said.
Burt said that it could be a matter of weeks or months before the judge makes a final ruling in the case and that an appeal could take another year or so after that.
Alcatel-Lucent spokeswoman Joan Campion said the company was pleased with Thursday's decision but would not say whether Lucent would go after other companies that support MP3s.
Microsoft and Alcatel are locked in a number of patent disputes including a suit over the video-decoding technology in Microsoft's Xbox 360 video game console.