In December 2021 S&P 500 touched DJI. The past reveals that every time S&P 500 touches DJI a major correction starts. That happened in 1929, in 2000 and in 2008 as the following chart shows. The only thing I have to add is that it looks like we're at the beginning of the current major correction.
I mean nothing more than the touch you see in the charts.
In the comparative chart, DJI is drawn in logarithmic scale and S&P 500 in regular scale. I don’t know why every time the regular S&P 500 touches (meets) the logarithmic DJI begins a major correction, but it is happening. You can try it yourself.
Perhaps the explanation is that for the regular line of S&P 500 to catch (touch or meet) the logarithmic line of DJI an extreme bull market was preceded and the prices had to be corrected.