Warren Buffett has consistently recommended low-cost S&P 500 index funds for many years and revealed that he has set investment instructions for the funds in his wife’s will: 90% of the funds should be invested in low-cost S&P 500 index funds (he recommends Vanguard products), with the remaining 10% invested in short-term government bonds. Buffett believes that this strategy will yield long-term returns superior to those of most portfolios managed by professional fund managers. He noted that the Vanguard S&P 500 Index ETF (VOO) has an annual expense ratio of just 0.03% and has delivered an average annual return of approximately 15% over the past decade.