I discussed in my interview with Investor’s Business Daily in 2011 titled “How Mike Shell Uses Relative Strength To Trade ETFs” some very basic concepts of how I apply proprietary relative strength systems to ETFs in a tactical ETF managed portfolio. Though we can develop all kinds of sophisticated algorithms to define relative strength, momentum, and directional price trends, at the end of the day the concept is very simple.

Up until now (a signal that something has changed) small company stocks where lagging large company stocks. To illustrate what that looked like, I stopped the relative chart below in Mid-May. You may observe that the blue line (the Russell 2000 index of small company stocks) was lagging and with a higher range of swings (more volatile). The black line is the S&P 500 stock index weighted toward larger stocks.

Source: http://www.stockcharts.com

Next we update the chart to today’s date. Over the past month, small companies caught up. However, they are now at the prior high, so we’ll find out in the weeks ahead if the relative out-performance continues, or if it finds some resistance and reverses back down.

Below I have zeroed out one side to express only the relative change of the small cap index while holding the large cap index steady. Here we see only the relative difference between small and large over the past year.

You can probably see how relative strength isn’t just about strength, there is also relative weakness. And, relative change oscillates over time.