LONDON — William Hill Plc, a London-based bookmaker, will pay out on a number of bets on the fate of Harry Potter because of an “ambiguous ending” to the seventh and final novel about the boy wizard.

The bookmaker repaid 50,000 pounds ($101,060) in wagers and a further 40,000 pounds to fans who either bet that he died, killed himself, or was killed by his nemesis Lord Voldemort.

“It was a fairly ambiguous ending, open to various interpretations, and so whatever way we settled the bets would have annoyed some people,” said Rupert Adams, a William Hill spokesman. “So we paid out on all the bets.”

The bets on the outcome of “Harry Potter and the Deathly Hallows” were the first William Hill had ever taken on the ending of a book. Three employees at the bookmaker read the novel by J.K. Rowling and failed to agree on the ending of the novel, Mr. Adams said.

“Now we have to hope that Rowling doesn’t bring out another Harry Potter book in the next two years,” Mr. Adams said. “We have already taken 12,500 pounds on that bet.”

The novel became the fastestselling book in British history last month after selling 2.65 million copies in the first 24 hours after its release.

Sales were 32% higher than for “Harry Potter and the Half-Blood Prince,” the previous book in the series, which sold 2 million copies in the first 24 hours, according to figures of Nielsen BookScan, an independent book trade monitoring service.

In America, the book sold a record 8.3 million copies on its first day, publisher Scholastic Corp. said. First-day sales surpassed the American record of 6.9 million copies set by Ms. Rowling’s sixth book in the series in 2005, New York-based Scholastic said.

Customers at Borders Group Inc., the second-largest American bookseller, bought 1.2 million copies of the book, the highest single-day sales of any title in the company’s history. Barnes & Noble Inc., the world’s largest bookseller, sold a record 1.8 million copies of the book in the first 48 hours of its release. In the first hour, the retailer sold 156 copies a second.

Ms. Rowling, 42, marked the release of the book at 12:01 a.m. on July 21 with a midnight signing session at London’s Natural History Museum, where she signed 1,600 copies. The author said in a BBC interview July 6 that she broke down in tears while writing the final book about the adventures of Potter and his friends at Hogwarts School of Witchcraft and Wizardry.

The six earlier novels in the series have sold more than 300 million copies, making Ms. Rowling wealthier than Queen Elizabeth II with a 545 million-pound ($1.1 billion) fortune, according to the Britain’s Sunday Times Rich List.

The latest movie in the series, “Harry Potter and the Order of the Phoenix,” which stars British actor Daniel Radcliffe as the bespectacled teenager, earned $77.4 million in America for Time Warner Inc. in its first weekend, making it the fourth-best film opening this year behind “Spider-Man 3.”

The first four movies grossed more than $3.5 billion in box office receipts, according to Web site Boxofficemojo.com. The first book in the series, “Harry Potter and the Philosopher’s Stone,” called “Harry Potter and the Sorcerer’s Stone” in America, was published in 1997.

The books are published by Bloomsbury Publishing Plc in Britain and Scholastic Corp. in America.