Select Energy Services (WTTR)

[lettruthringout]

So, yesterday was triple witching day

That is partial explanation for high volume at end of day. However, as noted earlier - there were 15 million shares traded. The highest number before that was 9.8 million on March 15 2024 (also triple-witching); next highest was 5.5 million one day in early 2024; there was a 4 million one day in 2020; and a 4 million one day in 2017. And 10 days in the 3 millions dating back between 2018 and 2024. All of the rest of the days dating back to 4/21/17 are less than 3 million. There are four triple witches per year. Something else is going on to explain yesterday's dark pool volume.

A brief triple witching primer and backstory
Triple witching, aka “freaky Friday,” originated in the 1980s with the introduction of stock index futures and options.

Unlike shares of stock, futures and options contracts expire, meaning they have a fixed lifetime. Impending expirations require market participants—in this case, mostly professional traders and money managers—to decide whether to exercise an option or let it expire, take or make delivery on a futures contract, or “roll” a futures or options position forward into a future month. That can all lead to a mad scramble, especially during the “witching hour,” the final trading hour (3 to 4 p.m. ET) of the triple witching day.

The convergence of the three expiration “witches” once every quarter effectively means that a bunch of buyers and sellers are all rushing to settle their positions before the closing bell. An oversimplified way to think about it is Black Friday shoppers mobbing a big-box retail store right when the doors open to grab a shiny new flat-screen TV.

Historically, triple witching days have been associated with elevated market volatility and sharp price swings, according to an article from Nasdaq, one of the top stock exchange groups. During triple witching, a confluence of factors “creates a complex market environment ripe for volatility.” Although market impact can vary from year to year, triple witching days “have consistently contributed to heightened trading activity and market turbulence,” the exchange said.