Forty-five days after its release, "The Dark Knight" has become the second movie in Hollywood history to collect $500 million at the domestic box office, totaling $502.4 million, according to estimates from distributor Warner Bros.

The film broke this record in only about six weeks, which is half the time it took Titanic to do so. However, “Titanic” kept its first position in the domestic charts, with $600.8 million.

Dan Fellman, head of distribution at Warner Bros., said he did not expect the Batman sequel to approach the sum that “Titanic” grossed, but to stop at about $530 million, although it could reach $550 million.

“I keep raising the number because it just keeps holding better than expected,” Fellman told the Associated Press.

Christian Bale also expressed his enthusiasm about the film’s success at the box office.

"It's wonderful!" the actor told Usmagazine.com. “But I'm not a business man. I just enjoy doing what I do and whatever happens after that is gravy,” he added.

All in all, the movie business is expected to set a summer revenue record of about $4.2 billion from the first weekend in May through Labor Day, according to box-office tracker Media By Numbers. This edges the previous summer record of $4.18 billion set last year, although the number of tickets sold – about 587 – dropped 3.5 percent.

“We would not be looking at a $4 billion summer if not for 'The Dark Knight,'” explained Paul Dergarabedian, Media By Numbers president. “In this case, one film made a huge difference.”

The films that together grossed 30 percent of the summer box office were all superhero tales: “The Dark Knight,” “Hancock,” Paramount's “Iron Man,” Universal's “The Incredible Hulk,” and “Hellboy II: The Golden Army.”