Derry Crown Court heard how a website set up by man from his Carnhill home could have cost film and TV producers as much as £120 million.
Paul Mahoney (30) of 372 Carnhill in Derry admitted four charges of concealing criminal property, conspiracy to defraud and acquiring criminal property in relation to infringing copyright on films and TV shows.
All of the offences occurred between April 2008 and May 2011.
A prosecution barrister told the court that it was 'a sophisticated fraud' that put at risk £120 million across the film and TV industry.
He said when police searched Mahoney's Carnhill home they found more than £82,000 in cash and they believed that overall he had made around £300,000 from his website.
The website enabled people to watch recently released or even unreleased films and TV shows and was free for users while Mahoney made his money from advertisers on the site.
On May 25 2011 the PSNI searched Mahoney's home and found the money.
At interview Mahoney made no comment but eventually agreed to sign over his domain to FACT before being bailed. However within three days Mahoney had set up another similar site.
A defence barrister Mr. Martin Rodgers said that the advertising companies who used Mahoney's website should also have questions to answer.
Judge Philip Babington said he would pass sentence on September 8.