From the link:
Once again, this is news arriving to confirm what’s already happened. The NYSI, measuring long-term breadth on the New York Stock Exchange, turned negative last week. That was the tell that the market’s advance was faltering. News can accelerate a decline, but no-news would have also but probably at a slower pace.
What we have now is a fast fall and based on one of my key charts it is likely too far, too fast. See the chart of SPY below and note nearly every time the average SPY pull-back (as displayed as a histogram) pierces one of lower green lines, it bounces, and sometimes runs. The Nasdaq Composite chart is showing the same pattern.
For the chart and more: