[chii]

This is exactly what happened with https://en.wikipedia.org/wiki/Archegos_Capital_Management#Ma... - they had what basically amounts to loans to several different banks (with each bank largely unaware of his other leveraged holdings at other banks).

When the stock price dropped and started to make margin calls on the loans, some of the banks had to take a loss as there wasn't enough liquidity to sell into.

banks don't like to be in this sort of situation - in this particular case, the banks just didn't do enough due diligence presumably.