NEW YORK (TheStreet) -- Momentum tech stocks have gotten slammed over the last three months. So have many biotech stocks.
The S&P 500 (^GSPC) isn't doing much better, either. So far this year, it's up roughly 1.5%.
But today something happened that every investor should see. It could be an enormous bullish signal for the stock market.
The NYSE Advance-Decline Line, in its simplest form, is a measure of all the stocks rising vs. all the stocks declining on a given day. The metric is a powerful way to gauge market breadth.
Today, the NYSE Advance-Decline Line hit a new all-time high on a cumultive basis. Think about what that means for second. Despite all the carnage in momentum stocks, and despite the fact the S&P 500 is only up 1.5%, there's still a large basket of stocks steadily increasing each day:
If you're wondering what predictive power the NYSE Advance-Decline Line might have, here's a chart of it before the 2008 Financial Crisis:
This article represents the opinion of a contributor and not necessarily that of TheStreet or its editorial staff.