NASDAQ PUMP repeat pattern over last 3 days >> algos? CTAS? Fed?

Check out the last 3 days of a very similar repeated pattern (3PM buy volume) that suggests some sort of mechanical trading. Is this algorithms, CTAS or the Fed?? (click link for better image) https://docs.google.com/presentation/d/e/2PACX-1vSGS7Qj3jl97TriYU3tHxV4wxZ3qRT4ndqg-eMg7txrxOc7VrdUlWE1G9Uk5RPX7ef71MjEk7iPZw2X/pub?start=false&loop=false&delayms=3000&slide=id.p