Since August, with the exception of a six-week period that ended earlier this week, the S&P has been trading below its negatively sloped 200-day moving average for the first time since 2011. The 200-day moving average is a widely used method to define whether an index is in a downtrend or uptrend. With this in mind, it would be easy to argue that the market has begun a downtrend. Over the last 25 years, the market has performed poorly when below a negatively sloped 200-day moving average and vice versa. Since 1990, the S&P has increased almost 1000%. Within that span, Investing only during periods when the S&P was below a downward sloping 200-day moving average would have resulted in a 75% LOSS of capital. Currently, the market has just barely ticked into this territory, so it is quite possible that a “whipsaw” like 2011 occurs, but it is worth acknowledging this development. MORE: Are Stocks Headed For A Bear Market?