The financial crisis, a severe contraction of liquidity in global financial markets, began in 2007 as a result of the bursting of the U.S. housing bubble. From 2001 successive decreases in the prime rate (the interest rate that banks charge their “prime,” or low-risk, customers) had enabled banks to issue mortgage loans at lower interest rates to millions of customers who normally would not have qualified for them, and the ensuing purchases greatly increased demand for new housing, pushing home prices ever higher. When interest rates finally began to climb in 2005, demand for housing, even among well-qualified borrowers, declined, causing home prices to fall. Partly because of the higher interest rates, most subprime borrowers, the great majority of whom held adjustable-rate mortgages (ARMs), could no longer afford their loan payments. Nor could they save themselves, as they formerly could, by borrowing against the increased value of their homes or by selling their homes at a profit. As the subprime mortgage market collapsed, many banks found themselves in serious trouble, because a significant portion of their assets had taken the form of subprime loans or bonds created from subprime loans together with less-risky forms of consumer debt. As millions of people lost their homes, jobs, and savings, the poverty rate in the United States increased, from 12.5 percent in 2007 to more than 15 percent in 2010. In the opinion of some experts, a greater increase in poverty was averted only by federal legislation, the 2009 American Recovery and Reinvestment Act (ARRA), which provided funds to create and preserve jobs and to extend or expand unemployment insurance and other safety net programs, including food stamps. Notwithstanding those measures, during 2007–10 poverty among both children and young adults (those aged 18–24) reached about 22 percent, representing increases of 4 percent and 4.7 percent, respectively. Much wealth was lost as U.S. stock prices—represented by the S&P 500 index—fell by 57 percent between 2007 and 2009 (by 2013 the S&P had recovered that loss, and it soon greatly exceeded its 2007 peak). Altogether, between late 2007 and early 2009, American households lost an estimated $16 trillion in net worth; one quarter of households lost at least 75 percent of their net worth, and more than half lost at least 25 percent. Households headed by younger adults, particularly by persons born in the 1980s, lost the most wealth, measured as a percentage of what had been accumulated by earlier generations in similar age groups. They also took the longest time to recover, and some of them still had not recovered even 10 years after the end of the recession. In 2010 the wealth of the median household headed by a person born in the 1980s was nearly 25 percent below what earlier generations of the same age group had accumulated; the shortfall increased to 41 percent in 2013 and remained at more than 34 percent as late as 2016. Those setbacks led some economists to speak of a “lost generation” of young persons who, because of the Great Recession, would remain poorer than earlier generations for the rest of their lives. As the financial crisis spread from the United States to other countries, particularly in western Europe (where several major banks had invested heavily in American MBSs), so too did the recession. Most industrialized countries experienced economic slowdowns of varying severity (notable exceptions were China, India, and Indonesia), and many responded with stimulus packages similar to the ARRA.
All taken from: https://www.britannica.com/topic/great-recession