I'm not a huge fan of using technical analysis on indicators, particularly when the y-axis on the chart is a percentage basis capped at 100%. 

But this T2108 chart, I believe has some merit as it pertains to support and resistance. For those needing a refresher, the T2108 measures the percentage of stocks trading above their 40-day moving average. I have used it quite a over the years to help determine the strength of market moves. 

Since the February lows were established, we have seen a very nice series of higher-highs and higher lows. Even when the market was selling off hard, the T2108 was holding up very well in the past two months. It also indicates that the lows put in February were "major lows" and that a break of those lows, should be considered a major change in the character of this market. 

But overhead, you have a series of lower-highs, with a perfectly drawn resistance level that may provide some major issues for stocks in the coming days. 

I'm not necessarily saying to sell everything, because I certainly am not, but raising the stops aggressively on existing positions, may be a wise thing to do, as retests of the resistance in the past, has led to some sharp sell-offs so far this year. 

(Click on image to enlarge)