Causes of Banking Crises

[Monirul Islam]

Banks can fail for several different reasons:

Bank Run: A bank occurs when many people try to withdraw their deposits at the same time. As much of the capital in a bank is tied up in investments, the bank's liquidity will sometimes fail to meet the consumer demand. This can quickly induce panic in the public, driving up withdrawals as everyone tries to get their money back from a system that they are increasingly skeptical of. This leads to a bank panic which can result in a systemic banking crisis, which simply means that all of the free capital in the banking system is withdrawn.
Stock Market Positive Feedback Loops: One particularly interesting cause of banking disasters is a similar positive feedback loop effect in the stock markets, which was a much more dynamic factor in more recent banking crises (i.e. 2007-2009 sub-prime mortgage disaster). John Maynard Keynes once compared financial markets to a beauty contest, where investors are merely trying to pick what is attractive to other investors. There is a profound truth to this, creating an interdependent and potentially self-fulfilling investment thought process. This can create dramatic rises and falls (bubbles and crashes), which in turn can throw banks with poorly designed leverage into huge losses.
Regulatory Failure: One of the simplest ways in which bank crises can occur is a lack of governmental oversight. As noted above, banks often leverage themselves to capture gains despite extremely high risks (such as over-dependence on derivatives).
Contagion: Due to globalization and international interdependence, the failure of one economy can create something of a domino effect. In 2008, when the U.S. economy collapses, the reduced buying power and economic output from that economy dramatically damaged all economies dependent upon it (which includes most of the world). This is called contagion.
The Great Depression
The Great Depression highlights how bank runs caused a banking crisis, which ultimately became a global economic crisis.The Great Depression in 1929 resulted from a variety of complex inputs, but the turning point came in the form of a mass stock market crash (Black Tuesday) and subsequent bank runs. As fear began to grip consumers across the United States, people became protective of their assets (including their cash). This caused a large number of people to the banks to withdraw, which in turn motivated others to go to the banks and get their capital out also. Since banks lend out some of their deposits, they did not have enough cash on hand to meet the immediate withdrawal requests (they became illiquid) and therefore went bankrupt. Within a few weeks this resulted in a systemic banking crisis.

Source: https://courses.lumenlearning.com/boundless-economics/chapter/fundamentals-of-banking-crises/