Question about studio versus distributor

[Seymour]

I'm trying to figure out why some BDs are attributed to the film studio that made the movie, and others are listed under the distributor of the BD.

All (or most) of the MGM films are listed under MGM, but they're distributed by Fox. But then take a movie like Minority Report--a Dreamworks title that's listed under Paramount here (presumably because it's distributed by them on BD). Or the movie Fanboys, which is a Weinstein title, but listed under Vivendi. Most other Weinstein films appear under Weinstein, even though they're distributed by Genius Products (besides the ones put out by Vivendi).

So what's the rule of thumb?