From the moment Avengers: Endgame began smashing ticket pre-sales records in early April, to its unprecedented $1.2 billion opening weekend debut a few weeks later, it seemed a foregone conclusion that Disney's (NYSE:DIS) latest Marvel epic would ultimately succeed 2009's Avatar -- which collected $2.788 billion in gross box-office sales a decade ago -- as the highest-grossing film of all time.

Not that it particularly matters. It's an understatement to say Avengers: Endgame has performed admirably for the House of Mouse, with worldwide box-office sales of $2.744 billion as of this writing. And even then, investors should remember Disney also owns the Avatar franchise (there are plans to make four sequels between late 2020 and 2027), thanks to its blockbuster acquisition of the majority of Twenty-First Century Fox's assets earlier this year.

People sitting in a theater with popcorn and drinks.

IMAGE SOURCE: GETTY IMAGES.

Waning momentum

But if even for the bragging rights and publicity of achieving the biggest-ever global box-office tally -- at least, without adjusting for inflation -- it's hard to blame Disney for wanting to set that new high mark. Still, few responsible industry watchers were willing to definitively predict Endgame would topple Avatar's long-standing cumulative $2.788 billion, as doing so would be dependent on the superhero-infused flick's ability to sustain its early success over the course of its box-office run.

It turns out that caution was merited. Avengers: Endgame's momentum has all but stalled entering its ninth weekend in theaters, adding a little under $7 million to its global total last weekend (down more than 20% from the previous weekend) and leaving it $44 million behind Avatar today.

Pushing Endgame over the edge

But make no mistake: Avengers: Endgame will almost certainly still end up in the No. 1 spot with the help of a special theatrical rerelease next week.

Speaking to Screen Rant yesterday, Marvel Studios President Kevin Feige confirmed Avengers: Endgame will be rereleased on Friday, June 28, "with a bit of a marketing push [and] a few new things at the end of the movie. ...

"If you stay and watch the movie, after the credits," Feige added, "there'll be a deleted scene, a little tribute, and a few surprises, which will be next weekend."

To be fair, beating Avatar probably isn't Disney's end goal, considering the timing of this news. Marvel's Spider-Man: Far From Home hits theaters on July 2, 2019, with a storyline that (mild spoiler ahead) sees the web-slinging hero dealing with the immediate aftermath of the events portrayed in Endgame. If I were a betting man, I'd say at least some of the new content ties directly into Spidey's impending adventure.

At the very least, the rerelease can serve the dual purpose of running up the score for Endgame and giving hard-core fans the chance to brush up on their Avengers canon before continuing the cinematic ride Marvel has worked so hard to cultivate.

If that means "beating" Avatar in the process, so much the better.