S&P 500 Monthly SELL Signal - 5th Sell Signal in 18 Years

The chart of the S&P 500's 17-month moving average triggered the 1st SELL signal since 2011, on August 31, 2015 the S&P 500's August 2015 monthly close was below the SELL line.

In the past 18 years it has issued SELLs  5 times, of which 2 were reversed back to BUYs (1998 and 2011), but two (2001 and 2007) signaled the beginning of major bear markets.