Ryan Reynolds in a test reel for a Deadpool movie. Sources: Google+ via Craig Kandiko. Twenty-First Century Fox owns the movie rights to Deadpool.

Forget about how big Marvel movies are right now. The X-Men may keep Twenty-First Century Fox, Inc. (FOXA) from making a Deadpool movie. Call it the downside of Hollywood's franchise era.

Unmuzzling the "merc with a mouth"

Ever since Ryan Reynolds played the pre-scarred Wade Wilson -- later to be known as "Deadpool" -- in 2009's X-Men Origins: Wolverine, there's been talk of a Deadpool movie. The buzz turned into a roar during last month's San Diego Comic-Con, when Blur Studio released one minute and 48 seconds of a long-discussed, eight-minute test reel. 

There's no way to know if more than 50,000 fans would actually buy a ticket to see a Deadpool movie in the theater. But what if they did? And what if they told their friends to see the movie? Again, we can't know for sure if that would happen, but we have seen a surge in search interest for the term "deadpool movie," which no doubt speaks to the buzz the test footage has generated.

A franchise unto himself

Yet, Reynolds' on-screen antics aren't the only reason there's demand for a Deadpool movie. Fans genuinely love the character, as the July comics sales charts show. All eight of his issues made the top 100 -- no easy feat:

Title

Rank
Est. Copies Sold to Retailers
Est. Gross Sales

Deadpool vs. X-Force #1

33

54,762

$218,500.38

Deadpool #31

39

49,930

$199,220.70

Deadpool #32

49

46,829

$186,847.71

Deadpool vs. X-Force #2

52

45,047

$179,737.53

Deadpool: Dracula's Gauntlet #1

61

40,790

$162,572.10

Deadpool: Dracula's Gauntlet #2

72

38,683

$154,345,17

Deadpool: Dracula's Gauntlet #3

76

37,449

$149,421.51

Deadpool: Dracula's Gauntlet #4

82

36,581

$145,958.19

Source: Diamond Comics Distributors via The Comics Chronicles.

In Deadpool vs. the X-Men, the X-Men win

No matter how good these numbers might look, they pale compared to the franchise potential of X-Men, which has spawned seven movies over 14 years, resulting in $3.05 billion in grosses as of this writing, Box Office Mojo reports. The latest in the series -- X-Men: Days of Future Past -- is currently the summer's top comic book adaptation, at $744 million worldwide. Fox has a huge financial incentive to expand this universe.

Deadpool wouldn't get the job done. Why? Deadpool isn't for children. He's a foul-mouthed, ultra-violent psychopath who wouldn't work well in a mainstream X-film. Smoothing the edges just to include him in the franchise could make for an awful movie, and terrible box office losses.

Then again, staying true to a violent character is no guarantee of success either. Lions Gate Entertainment's (LGF-A 1.37%) R-rated take on the vigilante known as The Punisher did poorly enough that the studio returned the film rights to Marvel. How the studio plans to handle him in future films is unknown at this point.

The illusion of independence

In comics, the major publishers have distinct imprints for its more adult-oriented properties. Marvel's Icon imprint published the Kick-Ass comics that subsequently became movies. DC's Vertigo line may be best known for Sandman, Neil Gaiman's award-winning series.

Most movie studios have similar imprints. At Fox, independent and horror films are released under the Fox Searchlight banner. Oscar winner 12 Years a Slave may be the most famous film to be distributed by the mini-studio.

Adding a Deadpool movie to the Fox Searchlight lineup wouldn't be too difficult, but it would also be as materially distinct from the remaining X-franchise as TheCW's Arrow is from Man of Steel, even though both are based on DC Comics properties. Franchising requires the cross-promotion that leads to lucrative licensing and merchandising deals.

Foolish takeaway

Personally, I'm holding out hope for a Deadpool movie. But the economic power of franchising is such that I expect Fox to keep this property as far away from the X-Men based films as it can.