The term financial crisis is applied broadly to a variety of situations in which some financial institutions or assets suddenly lose a large part of their value. In the 19th and early 20th centuries, many financial crises were associated with banking panics, and many recessions coincided with these panics. Other situations that are often called financial crises include stock market crashes and the bursting of other financial bubbles, currency crises, and sovereign defaults.[1][2] Financial crises directly result in a loss of paper wealth; they do not directly result in changes in the real economy unless a recession or depression follows.
Many economists have offered theories about how financial crises develop and how they could be prevented. There is little consensus, however, and financial crises are still a regular occurrence around the world.
Banking crisis
Main article: Bank run
When a bank suffers a sudden rush of withdrawals by depositors, this is called a bank run. Since banks lend out most of the cash they receive in deposits (see fractional-reserve banking), it is difficult for them to quickly pay back all deposits if these are suddenly demanded, so a run may leave the bank in bankruptcy, causing many depositors to lose their savings unless they are covered by deposit insurance. A situation in which bank runs are widespread is called a systemic banking crisis or just a banking panic. A situation without widespread bank runs, but in which banks are reluctant to lend, because they worry that they have insufficient funds available, is often called a credit crunch. In this way, the banks become an accelerator of a financial crisis.[3]
Examples of bank runs include the run on the Bank of the United States in 1931 and the run on Northern Rock in 2007. The collapse of Bear Stearns in 2008 has also sometimes been called a bank run, even though Bear Stearns was an investment bank rather than a commercial bank.
Banking crises generally occur after periods of risky lending and heightened loan defaults. [4] The U.S. savings and loan crisis of the 1980s led to a credit crunch which is seen as a major factor in the U.S. recession of 1990–91.
[edit] Speculative bubbles and crashes
Main articles: Stock market crash and Bubble (economics)
Economists say that a financial asset (stock, for example) exhibits a bubble when its price exceeds the present value of the future income (such as interest or dividends) that would be received by owning it to maturity.[5] If most market participants buy the asset primarily in hopes of selling it later at a higher price, instead of buying it for the income it will generate, this could be evidence that a bubble is present. If there is a bubble, there is also a risk of a crash in asset prices: market participants will go on buying only as long as they expect others to buy, and when many decide to sell the price will fall. However, it is difficult to tell in practice whether an asset's price actually equals its fundamental value, so it is hard to detect bubbles reliably. Some economists insist that bubbles never or almost never occur.[6]

Black Friday, 9 May 1873, Vienna Stock Exchange. The Panic of 1873 and Long Depression followed.
Well-known examples of bubbles (or purported bubbles) and crashes in stock prices and other asset prices include the Dutch tulip mania, the Wall Street Crash of 1929, the Japanese property bubble of the 1980s, the crash of the dot-com bubble in 2000–2001, and the now-deflating United States housing bubble.[4][7][8]
[edit] International financial crises
Main articles: Currency crisis and Sovereign default
When a country that maintains a fixed exchange rate is suddenly forced to devalue its currency because of a speculative attack, this is called a currency crisis or balance of payments crisis. When a country fails to pay back its sovereign debt, this is called a sovereign default. While devaluation and default could both be voluntary decisions of the government, they are often perceived to be the involuntary results of a change in investor sentiment that leads to a sudden stop in capital inflows or a sudden increase in capital flight.
Several currencies that formed part of the European Exchange Rate Mechanism suffered crises in 1992–93 and were forced to devalue or withdraw from the mechanism. Another round of currency crises took place in Asia in 1997–98. Many Latin American countries defaulted on their debt in the early 1980s. The 1998 Russian financial crisis resulted in a devaluation of the ruble and default on Russian government bonds.
[edit] Wider economic crises
Main articles: Recession and Depression (economics)
Negative GDP growth lasting two or more quarters is called a recession. An especially prolonged recession may be called a depression, while a long period of slow but not necessarily negative growth is sometimes called economic stagnation. Since these phenomena affect much more than the financial system they are not usually considered financial crises as such though there are clearly links between the two.

Declining consumer spendings.
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[9], a position supported by Ben Bernanke.[10]
[edit] Causes and consequences of financial crises