And there are also equity capital requirements along with rules as to what counts in tiers, Basel I & II.

Yes, and those are binding.

but should the Central Bank, for whatever reason,

Then the ATMs will stop working until parliament finds itself a new central banker. Which, depending on how far parliament has its head up its ass, may be before or after the angry mob who now cannot spend their wages to buy food finds itself a new parliament.

not supply the reserves that could make a given bank insolvent overnight. Wouldn't they normally 'resolve' that bank rather than not supplying reserves?

Illiquid, not insolvent. The bank will only become insolvent after they distress sell assets to cover their liquidity requirements.

But sane central banks never deliberately create bank runs on their own banking system like that. Partly because it's a game of musical chairs: All liquidity comes, in the final analysis, from the central bank. So if the central bank withdraws enough liquidity from the system that a bank must fold due to liquidity requirements, then (at least) one bank will fold when the music stops... and it may not be the bank the CB wanted to kill.

- Jake

Friends come and go. Enemies accumulate.