In 2015, a rumor surfaced from Bleeding Cool about the films' budget. They claimed the two-part event would cost a staggering $1 billion.
I mean, its two films for 1B. The profit from both of the films will go towards the bottom line making breaking even a guarantee. And they will profit big as well. But it doesn't need to have the largest ROI, all of the smaller individual films are the ones that are bringing in stupid amounts of profit. The team up films jobs are to deliver on bringing the characters together and hyping the next part of the 'universe' for another 2 years of solo films.