The financial system is the heart of free market economies. The 2007-2008 financial crisis raised concerns that the global financial and economic system might experience a truly substantial collapse. New financial instruments had proliferated to the degree that it had become impossible to calculate the market value of many of them, and so it had become impossible to know the market value of institutions that held them or that guaranteed them. The initial disaster occurred with the U.S. subprime residential mortgage market, but it quickly spread globally to institutions that held new financial instruments related to these mortgages. Firms that had guaranteed these financial instruments found that their net worth was disappearing, leading to concerns about the institutions that had relied on their guarantees. Meanwhile, new kinds of hedge funds introduced the risk of greater volatility, and they exposed investors to sudden shocks. Many banks were caught in this web and suddenly had to obtain additional equity capital in order to meet regulatory requirements and maintain the confidence of depositors. As a result of these developments, liquidity disappeared from the financial system. It seemed that recession in the United States was inevitable. Previous expectations that other economies had become "decoupled" for the United States were being replaced by fears that economies throughout the world would follow the United States into recession. Central banks reacted dramatically with attempts to reduce interest rates and to increase financial liquidity, and the U.S. government cut personal taxes through a tax refund program. It was not clear whether monetary and fiscal policies could prevent a long and deep recession. Debate arose concerning the advisability of a wide variety of new regulations that might be able to prevent future recurrence of such a financial crisis.
