The figure includes receipts from 10 p.m. shows on Tuesday, which accounted for about $4 million of the total, Daily Variety reported. Warner Bros. counted the Tuesday numbers as part of the first-day gross, the trade paper said, because with a run time of 2 hours and 37 minutes, there were few midnight shows Tuesday night.
The opening was the eighth-biggest Wednesday opening ever at the U.S. box office. "Spider-Man 2" had the biggest, with $40.4 million in 2004.
"We're thrilled with the opening of 'Superman Returns,'" Warner Bros. distribution president Dan Fellman told The Hollywood Reporter.
The studio has hopes that "Superman Returns" will outdo the Fourth of July weekend grosses for "War of the Worlds," which topped $112.7 million when the movie opened last year, Variety said.