To understand what is the sub-prime and the subsequent financial crises, it is imperative to understand that it is not a period of 4 or 5 years that caused the crises. The roots of the current crises were sowed around 15 years back.
Macro-imbalances
Many oil exporting, capital goods exporting countries and those countries that had a high savings rate had a massive current account surplus. On the other hand, there were countries like the US, UK, Ireland and others who were consuming more. This led to countries like China accumulated claims on the Government Securities of the US. The result of this was that the yields on the Government Securities fell from aroun 4 % in 1995 to about 0.75 to 1 % during the mid 2000's.
As the interest rates in the economy were related to the yields of the T - Bills, we saw an overall reduction in the interest rates
Financial Market Innovation
With the yields decreasing, investors looked for opportunities to increase their returns. This lead to surge in the securitised credit and other innovative products. Many financial pundits praised the role of credit derivaties claiming it as a means to reduce banking system risk and cut costs of credit intermediation. The risk of the derivatives was supposed to be passed on the end investors. This reduced the need of bank capital to be blocked. However, when the crises broke, it was observed that most of the toxic derivatives were not in the hands of end investors, but highly leveraged banks and bank-like institutions.
While some of the banks were practicing the policy of 'orginate and distribute', some of them were also in the business of 'acquire and arbitrage'. The banks that were orginating and distributing the loans, had to put in some amount of capital on their balance sheets. Under a condition of liquidity drying up, these banks faced a liquidity strains and potential losses. This was a major cause of failure of the Northern Rock.
There were the following results of the above mentioned activities:
- Growth within the financial sector: There was a phenomenal increase in the growth of financial sector debt as compared to the corporate debt. The growth of the relative size of the financial sector debt, increased the potential impact of the financial system instability on the real economy.
- Incease in leverage: creation of off-balance sheet vehicles (SIVs) and conduits - which were highly leveraged but whichwere not included in standard measures of either gross or risk adjusted leverage.
- Shadow Banking System
- Misplaced reliance on sophiticated math
- Mistimed haircuts, margins and triggers
- Lack of adequate captial buffers
The above is a brief to the understanding of the global financial crises.
A deeper understanding can be obtained from the Turner Review 2009 that explains the crises in a beautiful way!