Financial crisis

Wider economic crisis
Main articles: Recession and Depression (economics)
Negative GDP growth lasting two or more quarters is called a recession. An especially prolonged or severe recession may be called a depression, while a long period of slow but not necessarily negative growth is sometimes called economic stagnation.

Declining consumer spending.
Some economists argue that many recessions have been caused in large part by financial crises. One important example is the Great Depression, which was preceded in many countries by bank runs and stock market crashes. The subprime mortgage crisis and the bursting of other real estate bubbles around the world also led to recession in the U.S. and a number of other countries in late 2008 and 2009. Some economists argue that financial crises are caused by recessions instead of the other way around, and that even where a financial crisis is the initial shock that sets off a recession, other factors may be more important in prolonging the recession. In particular, Milton Friedman and Anna Schwartz argued that the initial economic decline associated with the crash of 1929 and the bank panics of the 1930s would not have turned into a prolonged depression if it had not been reinforced by monetary policy mistakes on the part of the Federal Reserve,^[11] a position supported by Ben Bernanke.^[12]
Causes and consequences
Strategic complementarities in financial markets
Main articles: Strategic complementarity and Self-fulfilling prophecy
It is often observed that successful investment requires each investor in a financial market to guess what other investors will do. George Soros has called this need to guess the intentions of others 'reflexivity'.^[13] Similarly, John Maynard Keynes compared financial markets to a beauty contest game in which each participant tries to predict which model other participants will consider most beautiful.^[14]
Furthermore, in many cases, investors have incentives to coordinate their choices. For example, someone who thinks other investors want to heavily buy Japanese yen may expect the yen to rise in value, and therefore has an incentive to buy yen, too. Likewise, a depositor in IndyMac Bank who expects other depositors to withdraw their funds may expect the bank to fail, and therefore has an incentive to withdraw, too. Economists call an incentive to mimic the strategies of others strategic complementarity.^[15]
It has been argued that if people or firms have a sufficiently strong incentive to do the same thing they expect others to do, then self-fulfilling prophecies may occur.^[16] For example, if investors expect the value of the yen to rise, this may cause its value to rise; if depositors expect a bank to fail this may cause it to fail.^[17] Therefore, financial crises are sometimes viewed as a vicious circle in which investors shun some institution or asset because they expect others to do so.^[18]