“Batman v Superman: Dawn of Justice” fell more sharply in its second weekend than initial estimates suggested.

The superhero film earned $51.8 million, a 69% drop from its $166 million debut. That fell short of Sunday’s estimate of $52.4 million, which would have represented a 68% decline. Most big blockbusters fall at least 50% in their second weekend of release, but this is a fairly steep plunge, suggesting the film’s receipts will be front-loaded. Going into the weekend, many analysts expected the film would fall roughly 60%.

This marks the most severe second weekend decline on a percentage basis for a major film featuring either Batman or Superman.

“Batman v Superman” has earned a hefty $260.9 million after two weeks of domestic release, but the expectations for the film are immense. Warner Bros. has a lot riding on its performance, and in many respects, “Batman v Superman” is less a film than a giant corporate “happening.”

The studio wants to establish a series of interconnected DC Comics adventures, with Batman, Superman, Wonder Woman and other heroes assembling for various Justice League films, sequels and spinoffs. It’s a model that copies a formula established by Disney’s Marvel Comics brand, which has reaped box office success with the “Avengers” films and standalone adventures featuring the likes of Iron Man and Captain America.

Reviewers have been cool to “Batman v Superman,” handing it a 29% “rotten” ranking on Rotten Tomatoes. Fan response has been mixed, as well. Social- media reaction has been healthy, but the picture earned a mediocre B CinemaScore, one of the worst ratings for a film featuring Batman or Superman.

Zack Snyder directed “Batman v Superman,” with Ben Affleck starring as the Dark Knight and Henry Cavill appearing as the Man of Steel. Warner Bros. spent $250 million to make the movie and tens of millions more to market the picture.