The S&P 500 is sending a technical signal that has marked the end of every bear market in modern history.

The benchmark’s 50-day moving average broke above the 200-day line on Thursday for the first time since the depths of the selloff in late March, forming a so-called golden cross. The price pattern is seen by some technical analysts as a positive omen as it frequently precedes sustained rallies.

Golden crosses for the S&P 500 have corresponded with the end of every major bear market in the last 70 years, according to Sundial Capital Research.

To be sure, using signals that worked in the past in today’s unique market environment isn’t a foolproof strategy. Investors learned that in March, when predictions for further stock-market losses were steamrolled as the S&P 500 embarked on a historic rebound. Still, there’s value in viewing a suite of technical and fundamental indicators together, and this one mostly sits on the positive side of the ledger.

Jason Goepfert, the president of Sundial, has analyzed these types of technical signals for decades and found they’re “barely useful” as a standalone metric. Take 2019 for example, when a golden cross registered to completely reverse a year later with the Covid-19 crash.

“Whether it was successful or not depends on one’s time frame,” Goepfert wrote in a report to clients.

What’s notable this time, though, is that the price pattern signals a reversal of what was a very negative spread between the two averages, with the 50-day average dipping more than 9% below the 200-day average.

“We wouldn’t put a lot of faith in the golden cross by itself,” Goepfert wrote. “The biggest reason for optimism is that it has reversed what had been a very negative medium- vs long-term trend, and that has led to big gains over the next 6-12 months every time over the past 70 years.”

This article was provided by Bloomberg News.