About short-selling and collateral damage, so to speak (hey! I like that one. But of course I tend to like most Audieisms....):
I worked it out to my satisfaction using a physical piece-of-paper 1 share of TSLA (somebody's business card, but never mind).
I like TSLA; you hate it; so through Fidelity you borrow it to sell it. Price rises and Fidelity tells you to increase your collateral; you're broke and can't and so things start unraveling. All that is clear to me and I'm sure to all.
So here's what happens next, I think:
Fidelity: "Cough up."
You: "Can't."
F: "Cough up"
You: "Still can't"
F: "Last chance"
You: "Hello, Nigeria Airlines?"
F: "OK. You're out. Audie, we have a problem here."
A: "Not my problem. YOU have a problem. Give me my share back thank you very much"
F: "Oh, fiddledeedee. Hello, AIG? You know that insurance we have regarding busted trades and margin collaterals? Well, we're cashing in on that policy. Audie's a spoilsport and wants that nasty piece of paper back and it's going to cost us a lot. So pay up."
F: "Okay Audie. Here's your share back.
AIG: "Hello shareholders? Umm, we had a really bad quarter. Thank goodness we'd reinsured through Swiss Re & Lloyds"
Lloyds: "So sorry old chappies, but we seem to have run into a spot of troublesomeness here."
Lather, rinse, repeat.
How'd I do?