(MONEY Magazine) – Mutual funds, says Mercer Bullard, are a remarkable confluence of money and society: With millions of people giving strangers cash to invest, he says, "it's the most stunning example of group trust that one could possibly imagine."

Sadly, sometimes that trust is abused: Funds can carry outsize expenses, for example, and directors can ignore shareholder priorities. So in 2000, a restless Bullard quit his job as staff attorney at the Securities and Exchange Commission and appointed himself advocate for mutual fund shareholders. Hey, why not? "I had my background and my knowledge and a lot of creativity and chutzpah," he says.

Bullard, now teaching law at Ole Miss, helped draft bills that prodded the SEC to reform fund governance; he continues to push a little-guy agenda, recently writing to the SEC to slam its interpretation of an investor protection rule. His advice to you? "The first thing you do when looking for a fund is eliminate all those that have above-average costs." Bullard records his work at funddemocracy.com.