Most likely a single or small number of GS large private clients liquidated some very large positions in these stocks. These stocks had already taken a huge beating resulting from a rather aggressive push in the ongoing rotation from high growth stocks into more value plays that lagged the market in 2020. All of these stocks were already down 20% or more since Feb.

My best guess is these clients had overly leveraged positions and needed to liquidate holdings in response to margin call.