Harvard, Princeton and Yale universities would have done well to heed the advice of Warren Buffett, who has long advocated investments in low-cost index funds while questioning the value of hedge funds. At least in the last fiscal year. Endowments with a big slice of their assets exposed to public equities were rewarded by a bull market in the year through June, when the S&P 500 and MSCI All Country World indexes returned 18 percent and 19 percent, respectively. Hedge funds returned just 8 percent on average, according to data compiled by Bloomberg.