In a 2005 study by Case-Shiller published by the National Bureau of Economic Research, the author found that people who invest in life cycle mutual funds are still exposed to significant risk, with very little opportunity to earn returns. Using a nominal 3% return for the investment, based upon portfolio allocations typical of life cycle funds, the author found that only 32% of hypothetical funds could outperform the 3% benchmark. This contrasts with his finding that if an investor purchases 100% of his portfolio in equities based upon the S&P 500, the portfolio would outperform the benchmark 98% of the time.