Francis Chou was a 25-year-old telephone repairman in Canada when he pooled 51,000 Canadian dollars from himself and six co-workers to start an investment club.

Thirty-one years later, Mr. Chou manages more than US$650 million for investors at his firm, Chou Associates Management Inc., and runs the best-performing bond fund in North America.

Mr. Chou's trajectory to the top of the bond-fund world shows how investors are tweaking tried-and-true strategies to boost returns and overcome chronically low interest rates. When he was starting out, Mr. Chou largely stuck to stocks and the classic value-investing methods made famous by Benjamin Graham and Warren Buffett.