According to a Securities and Exchange Commission document filed in Jan. 2008, and cited in the complaint, the firm had between 11 and 25 clients for the fiscal year ending Oct. 2007 and managed about $17 billion in assets in 23 different accounts.

Bernard Madoff Investment Securities, in addition to that private client practice, is also a market maker that trades with other dealers in bonds, the S&P 500 and NASDAQ, according to Bloomberg News. The firm was the 23rd largest market maker on NASDAQ in October, handling a daily average of about 50 million shares a day. The firm specialized in handling orders from online brokers in some of the largest U.S. companies, including General Electric Co. and Citigroup Inc., Bloomberg News reported.

But on Wednesday, Madoff allegedly told senior employees at his firm that his entire business was a fraud. According to the federal complaint, Madoff told those employees that he was "finished" and that "it's all one big lie." Madoff estimated "the losses from the fraud to be at least approximately $50 billion," the complaint states. At that time Madoff also told those employees that he intended to surrender to authorities, but before he did he planned to use $200-300 million he had left to make payments to "selected employees, family and friends," the complaint states.