Marvel has done an impressive job of stoking interest in this movie as a finale, convincing people this is not one of those MCU movies you can wait until Netflix or Disney+ for.
As for the weekend, this morning the range is between $349M-$356M off the widest theatrical release ever of 4,662.
It’s a good sign that the film opened far bigger than Avengers: Infinity War (and almost doubled the total from Avengers: Age of Ultron).
There are a lot of so-called “event movies,” but Endgame is unquestionably and undeniably a true event.