The final book about boy wizard Harry Potter broke a single-day record at Borders Group Inc., selling about 1.2 million copies worldwide.

This is the highest single-day sales of any title ever in Borders history, the book store company said on Sunday in a release. Borders is the second-largest chain of book sellers in the United States.

Fans have lined up outside book stores around the globe for a copy of Harry Potter and the Deathly Hallows -- the seventh and final volume of the series written by J.K. Rowling.

The sixth book in the series -- Harry Potter and the Half-Blood Prince -- sold 850,000 copies worldwide by Borders in 2005 during its first day of sales, Borders said.