
Currently the biggest-budget movie is Avatar: The Way of Water at $460M.
@mods This is an extremely confusing question, and the creator deleted their account. The Numbers lists The Force Awakens as already being above $500 million. Wikipedia agrees on The Force Awakens' page ("On a budget of $533 million, it is the 3rd most expensive film ever made."), but disagrees on the List of most expensive films page (where its budget is listed as $447 million---it seems like the discrepancy has something to do with a tax credit). Probably should just NA the question.
@polymathematic I would +1 to N/A-ing the question—I refrained from betting because it seemed like this was hard to solve. But technically I have a tiny loss from earlier on this market (maybe selling when it became clear this wasn’t easy to fix) so some other mod should make that call