The best way to prevent a bank run is not to run. A stampede isn't caused by the movement of a lone animal, but by the herd. It's a classic feedback loop.
No, the only way to prevent a bank run is to get everyone else not to run.
And since that's impossible, there's only one rational choice to make, which is to be first out the door.
This is bad! But it's true.
Unfortunately it’s very rare to have the knowledge and/or connections necessary to guarantee that you can not instigate a run, but still withdraw before the collapse.
Imagine the ALL-CAPS tweets and backdoor phone calls that could have been possible if these very same investors (who now rally behind the shuttered and reopened bank) could have called for calmness instead of panic. But that's not what happened. Once the run starts, you can't stop it.
> The best way to prevent a bank run is not to run.
That is irrational for every individual actor. There is very little downside in withdrawing the money and huge downside in not doing so.
The best (and only?) way to really prevent a bank run is for an actor that everyone trusts to aggressively step in and provide guarantees.
See for example the situation at Credit Swisse where the Swiss National Bank had to step in on March 16 to provide $54B in loans: https://www.aljazeera.com/economy/2023/3/15/credit-suisse-sl...