The National Association of Securities Dealers, the US watchdog, has formed a task force of senior professionals charged with ensuring there can be no repeat of the improper trading scandal which has rocked the $7trillion (€6trillion) US mutual fund business.

Robert Glauber, chairman and chief executive officer of the NASD, said: "Looking at mutual funds themselves and the practices used to sell them, a major part of the solution to the appalling abuses of the public trust we've seen recently is increased transparency."