Early reaction to X-Men: Days of Future Past has been overwhelmingly positive. Sources: Marvel Entertainment, YouTube.

If the reaction to X-Men: Days of Future Past on Twitter is any indicator, then Twenty-First Century Fox (NASDAQ:FOXA) is about to release the biggest comic book movie of the year.

But don't take my word for it. ComicBook.com has a list of what critics are posting to social media and ComicBookMovie.com has more positive reactions here. Reading them all, I can't help but think that X-Men: Days of Future Past, like Captain America: The Winter Soldier, is headed for a coveted "A" CinemaScore with audiences.

If I'm right, it would be a needed financial win for Fox. "A" movies tend to enjoy long, profitable runs in theaters. Look at Winter Soldier, which has surpassed Man of Steel and Thor: The Dark World with $681 million worldwide as of this writing. Marvel spent roughly $170 million to make the film and at least another $65 million to market and distribute the picture.

Mutants still in the minority
Fox's spending on X-Men: Days of Future Past must seem lavish by comparison. I'd guess more than $400 million after considering production, marketing, and distribution, which would put box office break-even at no less than $800 million and perhaps a great deal more.

That's a huge hurdle going by historical standards. Unlike Marvel's Avengers movies or Sony's Spider-Man epics, no Fox-produced comic book movie has ever earned even $500 million worldwide. Rather, the oft-reviled X-Men: The Last Stand ranks as the franchise's top grosser at a shade better than $459 million. A 75% improvement over that mark would rank as a major achievement in the history of Fox Studios.

And yet I think it's possible. Variety quotes insiders who predict the film will earn $250 million at the U.S. box office and open at $125 million when it debuts on Memorial Day weekend. Good numbers, certainly, but also provided before the press and others were privy to early screenings of the film.

Now that they've seen it -- and they're taking to Twitter to praise the movie -- I'm expecting those estimates to go much higher, and reignite a major franchise for Fox in the process. Do you agree? If not, which comic book movie do you expect to steal the summer? Leave a comment below to let us know your take, including whether you would buy, sell, or short Fox stock at current prices.

Michael Fassbender stars as the mutant Magneto in X-Men: Days of Future Past. Source: Marvel Entertainment.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.