In theory, this helps the banks to reduce risk, makes money for intermediaries who trade the securities, and allows the investors to pick tranches of debt that match their risk appetite.

ECONOMIST: Mortgage lending

To buy an actively managed equity fund (and even some indexed funds) usually costs an investor 5% in front-end fees, of which three-fifths or more goes to the person who sold the fund: almost 80% of retail investors buy their funds through intermediaries, says the Investment Management Association, a trade group.

ECONOMIST: Fund management