They don't get all of the foreign grosses right? Is there any way to estimate what the foreign numbers would have to hit to reasonably match the production budget?
Studios take in about 55% of the domestic gross and less (maybe 40%) overseas.
Given where the domestic gross is heading, Ghostbusters needed ~$325M worldwide to recoup its production costs (not considering marketing costs). It's looking like it will end up $75-100M short of that.