Could the community provide insights as to what happened and why it happened last Friday (May 26, 2023) with the S&P 500/ETFs?

Hey all. Just wanted to get a discussion going on how the markets moved like they did on Friday. Was it institutional software buys? Whales?

In my 4 years of day trading I can't recall many instances where we had such a bullish movement. Thanks in advance for any and all input! Just trying to understand this so I can know what's happening in similar instances in the future.