Dick Fuld, the chairman and chief executive of Lehman Brothers, is known within his brokerage as “the gorilla” because of his tough, no-nonsense approach to management.

Those who know Mr Fuld attribute his management approach to the lessons he learnt during a bitter dispute between the investment banking and trading divisions of Lehman in the early 1980s, a row that stymied the group and, many believe, precipitated its sale to American Express.

His no-nonsense approach should serve him in good stead as rumours of the demise of the bank continue to swirl around financial markets. The bank is seen as one of the most vulnerable on Wall Street in the wake of the sub-prime mortgage crisis.

Yet even despite its recent woes, Lehman remains a fairly happy ship. Since Mr Fuld took the top job in 1994, after Lehman's spin-off from American Express, he has worked tirelessly to stamp out dissent and to keep the franchise together. Brad Hintz, a former chief financial officer of Lehman, who left in 1998 and now works as an analyst at Sanford Bernstein, said: “Dick Fuld fired me, but he was a joy to work with - that's why Lehman is very happy.”

When Mr Fuld took over the reins at Lehman, it was a very limited business, operating in the money and corporate bond markets. Many thought it so weak that it would soon fail.

Yet he transformed the bank into a powerful global financial services group - albeit one far smaller than Goldman Sachs or Merrill Lynch - by taking it into areas such as private equity, corporate mergers and acquisitions, equity underwriting and proprietary trading.

Of course, Mr Fuld ultimately has to bear responsibility for the enormous losses that Lehman has suffered from investments relating to mortgages, but, as analysts point out, its vulnerability stems from the fact that it became a leader in the mortgage industry and therefore became more exposed to a housing crisis that took everybody in.

Ironically, Mr Fuld is seen as taking a much more hands-on role in the management of risk than many of his counterparts on Wall Street. Mr Hintz said that it is not uncommon for Mr Fuld to ask individual traders what is on their books and to tell them to offload assets he views as too risky.

The 62-year-old has a BA from the University of Colarado and an MBA from the Stern School of Business in New York. He has always worked at Lehman Brothers, joining the firm in 1969. Mr Fuld also serves on the board of directors of the Federal Reserve Bank of New York.