Some studies have suggested that the maximum natural mass that a black hole can reach, while being luminous accretors (featuring an accretion disk), is typically on the order of about 50 billion M ☉. However, a 2020 study suggested even larger black holes, dubbed stupendously large black holes (SLABs), with masses greater than 100 billion M ☉, could exist based on used models; some studies place the black hole at the core of Phoenix A in this category.