Large Volume Sells in last 5 minutes

Had a nice green portfolio at the opening bell today and ended the day down another 3.9%. Lucky I don’t pay attention to the day to day price swings. :wink: My question to the more experienced board members is what does it mean when EVERY stock I have had a very large volume trade in the last 5 minutes with a DOWN tick in price today?

My take is that means institutional investors are bailing on the higher risk growth stocks and is a bearish signal for the near term.

What do others interpret the high volume sell in the last minutes of the day to indicate?