The last days of MF Global

The collapse of MF Global in October 2011 was a remarkably powerful event: It destroyed the reputation of a famous man; it elevated a firm that no one had ever heard of to infamy; and it shattered public trust in the belief that brokerage customers' money is always safe.

In the months that followed, America's eighth-largest bankruptcy has become a spectacle and public scandal. Jon Corzine, the former U.S. senator, governor, and chief of Goldman Sachs who rode MF Global into the abyss, finds his legacy in tatters. And the hunt for the money continues, with investigators chasing $1.6 billion in customer cash that went  missing—something that's never happened before on Wall Street.

A six-month Fortune investigation into the failure of MF Global reveals a mismatch of tragic proportions: how a too-small company came together with a too-big CEO. Combining their mutual shortcomings—in ambition, controls, and discipline—simply proved toxic.

This story is based on more than seventy interviews with regulators, industry executives, legislators, lawyers, friends and family of Corzine, and people at all levels of MF Global. Fortune also gained access to hundreds of pages of confidential board minutes, internal reports, company emails, and other documents.