Banks don't keep all of their assets in cash in the safe. In its very simplest form, a bank takes money from depositors and pays a small "savings" rate. It then lends this money to borrowers at a higher rate. Every dollar in the safe is a dollar that isn't out earning interest, so the bank wants to only keep enough on hand to cover what customers will need for withdrawals.
I met an ex bank robber once. He and his "gang" attempted to rob a branch that was near a factory. The factory employed a number of immigrants who were fond of cashing their entire paycheques on pay day, so it would bring in a lot of extra cash every pay day. They timed their robbery for when the payroll money was present.
Unfortunately for them, the scheme had been rumbled, so the payroll delivery was fake and the police were waiting in plain clothes for them. He was shot in the neck but survived and learned to play bridge in prison, and in the fullness of time was released, where I met him and heard his story.
Any ways... It seems quite possible to me that a bank could be robbed but remain solvent.
Robert Heinlein makes good meat out of this misunderstanding of banking in his book 'Time Enough for Love'.
The nearly immortal protagonist often ends up being the banker in a small frontier towns. He routinely has to deal with mobs of people who attempt to "nationalize the bank" and are dumbfounded to discover that the bank does have all of the money in a safe.
Most Bitcoin exchanges - apparently including this one - only store a small portion of their funds in the wallet on their live server for exactly the same reason. They claim they can cover the loss.
I met an ex bank robber once. He and his "gang" attempted to rob a branch that was near a factory. The factory employed a number of immigrants who were fond of cashing their entire paycheques on pay day, so it would bring in a lot of extra cash every pay day. They timed their robbery for when the payroll money was present.
Unfortunately for them, the scheme had been rumbled, so the payroll delivery was fake and the police were waiting in plain clothes for them. He was shot in the neck but survived and learned to play bridge in prison, and in the fullness of time was released, where I met him and heard his story.
Any ways... It seems quite possible to me that a bank could be robbed but remain solvent.