Ant-Man and the Wasp Quantumania had a total production budget of $326.6 Million, making it the most expensive non-Avengers, MCU movie. Due to UK tax credits, they got back $50 Million which brought the final total to $276.6 Million.

According to Hollywood's rule of thumb, a movie needs to make ~2.5× its production budget in the box office to MAKE profit, which means this film needed to make at least $690 Million dollars in the worldwide box office and it only made $476 Million.

While Quantumania only spent 195 Million during pre-production and production as Forbes had reported last year, it's now been revealed that it blew over $131Million in post-production due its costly VFX.

The Marvels was in a similar situation where it had a production budget of $270 Million, but UK tax credits thankfully brought it down to $220 Million, although the movie still didn't turn profit.

UK's favourable tax credits is likely why Marvel Studios is moving out of Atlanta and into the UK for the filming of most their future productions (Fantastic Four, Blade, Vision Quest, Armor Wars, Avengers 5 and 6 and Shang-Chi 2).