Assuming 30 trading days horizon, S&P 500 is expected to generate 2.15 times more return on investment than Market. However, SP 500 is 2.15 times more volatile than Market Vectors Long Municipal Index ETF. It trades about -0.05 of its potential returns per unit of risk. Market Vectors Long Municipal Index ETF is currently generating about -0.82 per unit of risk. If you would invest  166,916  in S&P 500 on May 20, 2013 and sell it today you would lose (1,735) from holding S&P 500 or give up 1.04% of portfolio value over 30 days.