MF Global has filed for bankruptcy but how did it happen.  The MF Global trade is a version of what is known as a “repo-to-maturity” trade. Repos are a common financing technique that involve an agreement to sell and later repurchase of a security. Most commonly, these are very short-term agreements, often overnight. Please go to

http://www.moneycontrol.com/news/features/the-trade-that-killed-mf-global_610489.html

to read the entire article explaining the trade that sunk MF Global