John B. Neff, CFA, (born 1931) is an American investor, mutual fund manager, and philanthropist. He is notable for his contrarian and value investing styles as well as for heading Vanguard's Windsor Fund. Windsor became the highest returning, and subsequently largest mutual fund in existence during Neff's management—eventually closing to new investors for a period in the 1980s. Neff retired from Vanguard in 1995. During Neff's 31 years, from 1964 to 1995, Windsor returned 13.7% annually versus 10.6% for the S&P 500.