AMC Entertainment Holdings Inc (AMC)

[MastaBeta]

If they get a margin call it's done automatically. Broker starts liquidating all their long positions to begin covering short positions. Price shoots up from that. Triggers margin calls on other accounts with same short position. And same long positions for that matter.

Sell offs to acquire cash for covering will tank those long positions for others which then increases their margin ratios on top of SP spike for short positions. It's a domino effect similar to what started WWI.