Are these all heavily crypto invested? Was the run based on crypto/FTX and still exclusively or is it spreading to general panic?
Banks (especially in a fractional reserve banking system) are risky in that they generally have a mismatch between liabilities (the customer deposits which are supposed to be available on demand) and assets (which are usually longer-dated assets such as mortgage loans).
As long as there's no shock that could cause a run on the bank, everything can look like its smooth sailing. But if customers sense danger and start pulling out deposits, while there's an asset mismatch (and the current value of the asset might have fallen, due to changes in interest rates, or other reasons), the capital base can be wiped out very fast making the bank insolvent.
