All countries, developed or emerging, are equal before the banking crisis. This was shown in a study in December 2008, "Banking Crisis: An Equal Opportunity Threat" Carmen M. Reinhart and Kenneth S Rog off. Whatever the size of a country and state of development, no one is immune from a banking collapse. What are the causes of banking crises? Are they different from one country to another and according to their characteristics (size, characteristics, types of loans and financing granted)?

The study, which analyzed 120 seizures - from the early nineteenth century to 2008 - none of these elements can be taken into account. The only truly convincing explanation is the

They show in particular that there are close links between the movement of capital movements, credit and asset prices, especially in regard to property prices and stock prices (see chart below).

The consequences of banking crises always mean that the country is rich or poor, a deterioration of public finances. This explosion of deficits and public debt resulting from the need for states to achieve a double objective. First consolidate or save the banking system by replacing it in its function of financing the economy. On the other hand overcome the lack of private demand (household consumption and business investment). A policy that entails a strong increase in aggregate demand through government spending is leschéma Keynesian-classical).

Carmen M. Reinhart and Kenneth S Rogoff note in particular that of 26 banking crises analyzed, 18 of them - or in approximately 70% of cases - the financial sector had been liberalized during the previous five years.

The fiscal cost of bailouts and recapitalization of banks are not solely responsible for the deficit. It must also reckon with the cost in terms of public finances of a sharp decline in bank financing to the economy. The drop in production led to a sharp drop in tax revenue - with lower incomes - and in parallel to an explosion of public spending - given the development plans of reviving the economy. This situation results in an average increase of 86% of public debt during the three years following the crisis.

As stated Michel Aglietta in his latest book "Crisis and Renewal of the Finance (3), the historian Charles Kindleberger had already demonstrated the recurrence of financial cycles. They can be periodized in the same way as they have no precise regularity and not all have the same amplitude. However they are similar and are characterized by the sequence of five phases:

- The rise. This phase follows a recession or a strong slowdown. Growth is driven by investment. It is financed by credit expansion which operates in parallel with higher incomes. - Euphoria. This phase is characterized by a runaway credit relative to income and an acceleration of asset prices. This is transmitted to other countries where capital flows freely to the international level. He then indebtedness under evaluation and concomitant risks taken by investors and economic agents borrowers. - The climax and turning. The situation of actors becomes increasingly fragile with increasing leverage. Approaching the peak, a catalytic event but then the unexpected product market turnaround. - The ebb and the establishment of pessimism. Two forces then lead the market in the crisis, the obsession with liquidity in debt and agents the rise of risk aversion to liquidity providers. If this concern reached the banks there when rationing of credit (credit crunch). - Deflation of debt and balance sheet restructuring.'s Debt is then the objective of this phase. All players now want to deleverage. It is however hampered by the declining value of collateral and then translated by write-downs and losses.

This shows that the credit market affects the asset. Asset markets are speculative in nature and evolve based on investors' expectations about their future income (capital gains on disposals and dividends for shares or coupons for bonds).

These expectations of future earnings also depend on interest rates, the latter playing the role of discounting these future income streams. Anticipation of future courses is the speculative component and value the fundamental value of the asset.

Finally, the asset price depends on credit that allows the fund. The higher the volume of credit rises, the more asset prices rise as credit abundant always attracts more buyers.

So there is a close interdependence between asset markets and credit markets. This interdependence is self-perpetuating and there is no restoring force, not self and therefore violent crisis.