Early predictions had looked hopeful, with an estimated $120million take at the domestic US box office alone.
Instead, Justice League is expected to only bank $96million, making it the lowest opening of all the five DCEU movies so far.
The movie is predicted to take a further $185.5million in the international markets, bringing the total to just over $285 million.
Most blockbusters these days hope to make the major part of their money in the first week or two of release. With reports of the enormous budget and marketing costs coming in at around $600million, there is an awful lot of work for the superhero movie to do before it even breaks even.
To compare the performance with the dreaded Marvel rivals, the recent Thor Ragnarok took almost £123million in the US on its opening weekend.

vCard.red is a free platform for creating a mobile-friendly digital business cards. You can easily create a vCard and generate a QR code for it, allowing others to scan and save your contact details instantly.
The platform allows you to display contact information, social media links, services, and products all in one shareable link. Optional features include appointment scheduling, WhatsApp-based storefronts, media galleries, and custom design options.
The third movie in the franchise has already raced to an enormous $740million worldwide in just two weeks on a reported budget of $180million.
Justice League’s own predecessors all out-performed a movie that was hoped to finally establish the franchise as a credible and fan-pleasing comicbook property.
JUSTICE LEAGUE REVIEW: IGNORE THE CRITICS THIS IS WHAT A LIFELONG DC FAN SAYS
DC’s interconnected cinematic universe movies all performed better, with Batman V Superman: Dawn of Justice on $166 million, Suicide Squad ($133 million), Man of Steel ($116 million), and Wonder Woman ($103 million).
This may partly reflect a recent decline in ticket sales overall, but major franchises like Star Wars, Marvel, Fast & Furious and Disney’s live action remakes have all posted billion dollar hits.
So, who or what is to blame?