Bernard Madoff began 2008 with a reputation for savvy investing and $17bn under management from dozens of funds and hundreds of investors. He ends the year with his reputation in ruins amid allegations he defrauded investors out of as much as $50bn.

The story of how this secretive investment manager, a former chairman of Nasdaq, crashed and burned over several days in December adds to the fragile sentiment in the investment community already reeling from this year’s implosion of the credit markets. It also raises fresh questions about regulatory oversight.