So a lot of the selling was madatory selling because of margin calls. As the price falls people have to sell to maintain a margin level. If a large number of people Hodl. And there is a then market and then a bunch of people take out margin and the price starts to fall, eventually some gets a margin call. They have to sell. That causes the next person to sell, and that causes the next person to sell and so on. They fall like dominoes and the market can not absorb the impact. If you even took out a small loan when it was at 30 when it hit 4 you are likely to have a margin call. (or be forced to sell to and pay back that loan before then. Either way. It adds to the selling. This happens regularly in the Stock and futures markets.