By Susan Lund, Asheet Mehta, James Manyika, and Diana Goldshtein
It all started with debt.
In the early 2000s, US real estate seemed irresistible, and a heady run-up in prices led consumers, banks, and investors alike to load up on debt. Exotic financial instruments designed to diffuse the risks instead magnified and obscured them as they attracted investors from around the globe. Cracks appeared in 2007 when US home prices began to decline, eventually causing the collapse of two large hedge funds loaded up with subprime mortgage securities. Yet as the summer of 2008 waned, few imagined that Lehman Brothers was about to go under—let alone that it would set off a global liquidity crisis. The damage ultimately set off the first global recession since World War II and planted the seeds of a sovereign debt crisis in the eurozone. Millions of households lost their jobs, their homes, and their savings.