The average U.S. stock fund plummeted 37.9% in 2008, slightly worse than the Dow Jones Industrial Average's 33.8% loss. It was the Dow's worst year since 1931, when it declined by more than 50%. Meanwhile, the Standard & Poor's 500 Index fell 37%, its worst performance since 1937.
The best-performing specialty category was healthcare funds, which fell 23.1% in 2008, and the worst-performing was communications funds, down 49.9%. Even conservative allocation funds declined by an average of 18.1%, as did target-date funds, which gave up 22.3%. Regardless of the fund category, the declines were all about the same; large-cap mutual funds declined 37.7%, mid-caps fell 38.5% and small-caps lost 36.1%.