coca cola serving size

on a 12 ounce can it says the serving size is 1 can.
on a 20 ounce bottle it says the serving size is 1 bottle (used to be 2.5 servings, but today i saw it now says 1 bottle).
but on a 2 liter of coke the serving size is 8 ounces...

who comes up with "serving sizes"

I think there was a push recently to stop listing the nutrition facts on single serve containers broken up into multiple servings because it was misleading. It really doesn't matter what you consider a serving as long as the nutrition information is accurate.

If you buy a can of coke, you're going to drink the whole thing. Same goes for a 20oz bottle. So the nutrition information on the panel should be reflective of what you're about to consume.

If you are buying a 2L its going to be broken up, so theres more leeway in how the nutrition panel can be made.