Comment by scoofy

>The worst comes when there are too many investors with margin debt and they start to get margin calls at the same time. This causes prices to drop and it triggers even more margin calls, starting an avalanche where stock prices drop just from forced sells.

Yep, liquidity matters so much in the short run, and people getting margin calls will get disproportionately hurt. It's the same reason why GME shot up in price even though it was just marginally profitable, all the liquidity dried up, and there was still pressure on the buy side. I'm a big fan of Taleb when it comes to finance: the #1 rule should always be "don't blow up." Trading on margin is a good way of allowing that to be a possibility.