Warner Bros. brought in a pair of extra financiers to split the costs (and profits) for cost $55 million to produce, which is a pretty modest sum for a tentpole nowadays (especially of the comic book-based variety). However, in less than two weeks of release, it's already grossed north of $500 million at the global box office.
Nevertheless, WB was understandably wary about making the movie in the first place. Phillips spent about a year convincing the studio Logan have proven there's a sizable crowd for R-rated comic book adaptations in recent years, WB was still pretty anxious after giving Joker the go-ahead.
In fact, according to an article by the New York Times, the studio was so worried, they brought on two additional co-financiers (Bron Studios and Village Roadshow) to reduce the risk of them losing money on Joker. As a result, all three of them will be sharing the movie's profits.
Given the prior success of Deadpool and Logan (not to mention, Justice League still took home $658 million around the globe. With a far lower price tag than either of those films, it would've come as a shock if Joker - a movie based on the Caped Crusader's most famous enemy - had failed to recoup its budget, in spite of having to deal with the restrictions of an R rating.
To be fair, though, it's easy to look back at this point and argue that WB was too worried about Joker's commercial prospects. The studio suspect the film would make waves, but had no reason to think it would its greatest marketing trick. If they had, they wouldn't have split up the movie's costs and profits the way they did. Best to not feel bad for them, though; with Joker now eying a billion dollars at the global box office and well on its way to becoming an Oscar contender, WB are (much like Arthur Fleck) laughing their way all the way to the bank.
Source: NYT
