The WIPO, the closest the internet has to a ruling body, ordered that the respondent, known as HarperStephens of California, had "no rights or legitimate interests" in the domain names which were registered "in bad faith".
On Thursday, it was granted ownership of 107 Potter-related internet domain names in a ruling by the United Nations World Intellectual Property Organisation (WIPO), based in Geneva.
The names - which include harrypotterbooks.org, harrypotterfilm.org and harrypotterstudios.com - had been registered on or around the day the news broke that the first Potter book was to be made into a film.
The WIPO, the closest the internet has to a ruling body, ordered that the respondent, known as HarperStephens of California, had "no rights or legitimate interests" in the domain names which were registered "in bad faith".
Wizard sales
The series of books about the young apprentice wizard have been a runaway success.
Millions of copies of themost recent book, Harry Potter and the Goblet of Fire, have been sold in more than 30 different languages, making author JK Rowling a multi-millionaire.
It sold more than 370,000 copies on its first day in the UK.
The first book, Harry Potter and The Philosopher's Stone, is being made into a Warner Brothers film, due for release in November 2001.
Cybersquatting
Cybersquatting is where individuals seek to profit by registering someone else's trademarked name.
What is at stake are millions of dollars in revenue from the increasingly lucrative business of signing up websites.
Many celebrities including singer Madonna, actress Julia Roberts and the family of late rock star Jimi Hendrix, have won the right back to their domain names.
However, British singer Sting lost his case on the grounds that "sting" is a commonly-used English word.
The WIPO's dispute settlement service for cybersquatting was first set up a year ago to allow victims a chance to get their domain names back without fightly a costly legal battle or paying large sums of cash.
It has settled more than 900 cases, mostly against the cybersquatter.