Correlation does not mean causation. Nonetheless, we can't rule out that the handful institutions put $2,300,000,000,000 in cash into the Reverse Repo Operations before slowly placing it in the S&P 500, except for when the bond and treasury markets gave favorable interest rates.

I believe that the two entities likely had a coincidence that either strongly moved together or in opposite direction for months at a time and these charts likely are meaningless. I would love to get some feedback and recommendations how to improve this analysis.

https://github.com/adam-s/reverse_repo_corr/blob/main/reverse.ipynb