A bank run happens when many customers fear that a bank will become insolvent and withdraw their money simultaneously. In this video, you'll learn a simple way to understand this concept through an easy and brief explanation. As people withdraw cash, the bank uses up their reserves and cannot cover withdrawals. If multiple banks endure runs at the same time, it can become what’s known as a bank panic. Although, it's important to note that bank runs are typically driven by fear rather than actual insolvency.