Comic book superheroes may be an American creation, but these days they are earning their keep at theaters outside the United States.
Ever since "Thor" stormed theaters in 2011, superhero films have taken in well above half of box-office earnings abroad. In the past two years, eight out of 11 superhero films earned between 58 and 66 percent of ticket sales outside the United States. Those foreign returns are now underwriting the future of lucrative franchises, say analysts.
The stakes are high. Disney Studios will spend billions to produce Marvel movies with intertwined storylines over the coming years. Warner Bros. looks prepared to follow suit with its DC Comics properties.
"It's a recipe for success, but a recipe that has to have ingredients from all over the world," said Paul Dergarabedian, president of Hollywood.com's box-office division.
To justify a sequel, studios need to drum up about $400 million in ticket sales, said Jeff Bock, an analyst at ERC Box Office, and it's becoming harder to hit that target in North America alone.
You don't have to look farther than this summer's "The Wolverine," said Bock. It had the weakest U.S. opening of all six films in the "X-Men" franchise, but scored the biggest opening weekend abroad. To date, 64 percent of tickets sales for "The Wolverine" have come from overseas.
"This is a huge reversal, and we're going to see this next year with the new 'X-Men' film. We're going to see an even wider margin," said Bock.
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Comic book adaptations are catching up to the broader trend in Hollywood. Foreign revenue has accounted for about two-thirds of U.S. studios' box-office haul for years. In the decade up to 2011, comic book adaptations typically pulled in between 45 and 55 percent of ticket sales overseas.
While Europe, Japan and Australia remain big markets, much of the growth is coming from big emerging nations.
Part of that is because of the explosion of modern theaters with IMAX and 3-D screens in emerging markets. "The novelty has worn off here, but it's still very big in China, in Russia, in Brazil," said Bock.