SSR (Sustainability and Systemic Resilience)
Also called
SCR governs how much a club spends relative to its revenue. SSR governs whether the club is financially robust enough to keep operating, using resilience-style tests of liquidity, going-concern status and balance-sheet position.
The two run in parallel: passing SCR does not exempt a club from SSR, and the tests have their own calendar. The Premier League's SSR test date is 7 July, with 31 October applying to promoted clubs.
The published detail on how each SSR test is calculated is limited, so this site describes the framework in general terms rather than quoting thresholds it cannot source.