In 2008, the American housing bubble unexpectedly burst sending property values plummeting. Thousands of American families had ceased refinancing their household loans. Their adjustable-rate mortgages far outpaced the value of their homes, causing a wave of foreclosures across the country. An estimated nine million households lost their homes because the subprime loans they had subscribed to were subject to speculation on the stock market and to predatory lending, making them incredibly toxic. In the meantime, banks and insurance companies, which had neither anticipated the bubble nor the high number of failed payments, faced huge difficulties. Real estate is not only the largest single form of wealth, it is also the most important form of collateral for borrowing.