When Michael Milken entered the federal prison camp at Pleasanton, California, in 1991, it was tempting to conclude that an era in finance had come to an end.

From his X-shaped desk at Drexel Burnham Lambert in Los Angeles, Mr Milken and his weapon of choice – the high-yield bond – had revolutionised Wall Street in the 1980s, developing a market for the debt of young companies lacking an investment grade rating and raising billions for corporate raiders who could not persuade traditional investment banks to support them. But by the time he pleaded guilty to six counts of violating securities and reporting laws, his bank had collapsed, the high-yield market had fallen off a cliff and he had come to be portrayed in the popular press as a Wall Street Icarus brought to earth.