Environmentally responsible business practices don't always lead to a decrease in profits. Professors Michael Russo and Paul Fouts examined the economic and environmental performance of 243 companies over a two-year period. They found that companies with superior environmental performance had higher returns on investment compared to their competitors. The study measured environmental performance as going beyond complying with regulations to prevent pollution at its source. Companies rated with superior environmental performances include Heinz, American Express, Ford, and Amoco.