John B. Neff, CFA, (September 19, 1931 – June 4, 2019) was an American investor, mutual fund manager, and philanthropist. He was 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 thirty-one-year tenure at Windsor (1964 to 1995), the fund returned 13.7% annually versus 10.6% for the S&P 500.