AU Optronics has been fined $500 million by a US judge for price fixing in the market for liquid crystal display panels.
US District Judge Susan Illston in San Francisco also handed down three-year prison sentences to two individual defendants involved in the case.
A jury had convicted the company and two AU executives, Hsuan-Bin Chen, 60, and Hui Hsiung, 58, in March. Former AU Chief Executive L.J. Chen, who remains a top executive at the company, was cleared.
According to Reuters, the company's shares jumped as much as five percent after investors breathed a sigh of relief that the fine wasn't larger.
AU was charged as part of an investigation into an alleged price-fixing cartel between 1999 and 2006.
Prosecutors had accused company executives of meeting more than 60 times at luxury hotels to fix prices of LCD panels. They claimed that the conspiracy cost the US economy billions of dollars.
AU has said it would appeal its conviction as it insisted that the company "competed fiercely" and that the exchange of information between companies was not illegal.
Even if it was, AU argued it should be fined no more than $285 million while US antitrust prosecutors called for a $1 billion fine.
AU was the sole Asian LCD maker to plead not guilty
LG Electronics had been fined $400 million because it gave the prosecution a lot of evidence to nail the others, prosecutors pointed out.
The judge put the company on probation for three years including implementation of a compliance and ethics program. The company was ordered to pay the fine over three years.
Chen and Hsiung were sentenced to three years in prison for making "poor choices and bad judgement".