This credit freeze brought the global financial system to the brink of collapse. The response of the Federal Reserve, the European Central Bank, the Bank of England and other central banks was immediate and dramatic. During the last quarter of 2008, these central banks purchased US$2.5 trillion of government debt and troubled private assets from banks. This was the largest liquidity injection into the credit market, and the largest monetary policy action, in world history. Following a model initiated by the United Kingdom bank rescue package, the governments of European nations and the USA guaranteed the debt issued by their banks and raised the capital of their national banking systems, ultimately purchasing $1.5 trillion newly issued preferred stock in their major banks. In October 2010, Nobel laureate Joseph Stiglitz explained how the U.S. Federal Reserve was implementing another monetary policy —creating currency— as a method to combat the liquidity trap. By creating $600 billion and inserting[clarification needed] this directly into banks, the Federal Reserve intended to spur banks to finance more domestic loans and refinance mortgages. However, banks instead were spending the money in more profitable areas by investing internationally in emerging markets. Banks were also investing in foreign currencies, which Stiglitz and others point out may lead to currency wars while China redirects its currency holdings away from the United States.

What brought the global financial system to the brink of collapse?