On Wall Street, his name is legendary. With money he had made as a lifeguard on the beaches of Long Island, he built a trading powerhouse that had prospered for more than four decades. At age 70, he had become an influential spokesman for the traders who are the hidden gears of the marketplace. But on Thursday morning, this consummate trader, Bernard L. Madoff, was arrested at his Manhattan home by federal agents who accused him of running a multibillion-dollar fraud scheme perhaps the largest in Wall Streets history.
Regulators have not yet verified the scale of the fraud. But the criminal complaint filed against Mr. Madoff on Thursday in federal court in Manhattan reports that he estimated the losses at $50 billion. We are alleging a massive fraud both in terms of scope and duration, said Linda Chatman Thomsen, director of the enforcement division at the Securities and Exchange Commission. We are moving quickly and decisively to stop the fraud and protect remaining assets for investors.
Andrew M. Calamari, an associate director for enforcement in the S.E.C.s regional office in New York, said the case involved a stunning fraud that appears to be of epic proportions.
According to his lawyers, Mr. Madoff was released on a $10 million bond. Bernie Madoff is a longstanding leader in the financial services industry, said Daniel Horwitz, one of his lawyers. He will fight to get through this unfortunate set of events.
Mr. Madoffs brother and business colleague, Peter Madoff, declined to comment on the case or discuss its implications for the Madoff firm, which at one point was the largest market maker on the electronic Nasdaq market, regularly operating as both a buyer and seller of a host of widely traded securities. The firm employed hundreds of traders.
There was some worry on Wall Street that Mr. Madoffs fall would shake more foundations than his own.
According to the most recent federal filings, Bernard L. Madoff Investment Securities, the firm he founded in 1960, operated more than two dozen funds overseeing $17 billion.
These funds have been widely marketed to wealthy investors, hedge funds and other institutional customers for more than a decade, although an S.E.C. filing in the case said the firm reported having 11 to 23 clients at the beginning of this year.
At the request of the Securities and Exchange Commission, a federal judge appointed a receiver on Thursday evening to secure the Madoff firms overseas accounts and warned the firm not to move any assets until he had ruled on whether to freeze the assets.
A hearing on that request is scheduled for Friday.
Regulators said they hoped to have a clearer picture of the losses facing investors by that court hearing.
We have 16 examiners on site all day and through the night poring over the records, said Mr. Calamari of the S.E.C.
The Madoff funds attracted investors with the promise of high returns and low fees. One of Mr. Madoffs more prominent funds, the Fairfield Sentry fund, reported having $7.3 billion in assets in October and claimed to have paid more than 11 percent interest each year through its 15-year track record.
Competing hedge fund managers have wondered privately for years how Mr. Madoff generated such high returns, in bull markets and bear, given the generally low-yielding investment strategies he described to his clients.
The numbers were too good to be true, for too long, said Girish Reddy, a managing director at Prisma Partners, an investment firm that invests in hedge funds. And the supporting infrastructure was weak. Mr. Reddy said his firm had looked at the Madoff funds but decided against investing in them because their performance was too consistently positive, even in times when the market was incredibly volatile.
But the essential drama is a personal one one laid out in the dry language of a criminal complaint by Lev L. Dassin, the acting United States attorney in Manhattan, and a regulatory lawsuit filed by the S.E.C. According to those documents, the first alarm bells rang at the firm on Tuesday, when Mr. Madoff told a senior executive he wanted to pay his employees their annual bonuses in December, two months early.
Just days earlier, Mr. Madoff had told another senior executive he was struggling to raise cash to cover about $7 billion in requested withdrawals from his clients, and he had appeared to have been under great stress in the prior weeks, according to the S.E.C. complaint.
So on Wednesday, the senior executive visited Mr. Madoffs office, maintained on a separate floor with records kept under lock and key, and asked for an explanation.
Instead, Mr. Madoff invited the two executives to his Manhattan apartment that evening. When they joined him there, he told them that his money-management business was all just one big lie and basically, a giant Ponzi scheme.
The senior employees understood him to be saying that he had for years been paying returns to certain investors out of the cash received from other investors.
In that conversation, according to the criminal complaint, Mr. Madoff stated that he was finished, that he had absolutely nothing.
By this account, Mr. Madoff told the executives he intended to surrender to the authorities in about a week but first wanted to distribute approximately $200 million to $300 million to certain selected employees, family and friends.
On Thursday morning, however, he was arrested on a single count of securities fraud, which carries a maximum penalty of 20 years in prison and a maximum fine of $5 million.
According to the S.E.C., Mr. Madoff confessed to an F.B.I. agent that there was no innocent explanation for his behavior and he expected to go to jail. He had lost money on his trades, he told the agent, and had paid investors with money that wasnt there.
Although not a household name, Mr. Madoffs firm has played a significant role in the structure of Wall Street for decades, both in traditional stock trading and in the development of newer electronic networks for trading equities and derivatives.
In building those new trading networks, his firm had formed partnerships with some of the largest brokerage businesses on Wall Street, including Goldman Sachs and Merill Lynch.
Mr. Madoff founded Bernard L. Madoff Investment Securities in 1960 and liked to tell interviewers about earning his initial stake by working as a lifeguard at city beaches and installing underground sprinkler systems.
By the early 1980s, his firm was one of the largest independent trading operations in the securities industry. The company had around $300 million in assets in 2000 at the height of the Internet bubble and ranked among the top trading and securities firms in the nation.
Mr. Madoff ran the business with several family members, including his brother Peter, his nephew Charles, his niece Shana and his sons Mark and Andrew.
Vikas Bajaj and Gretchen Morgenson contributed reporting.