Fidelity are closer to a proper broker where things like margin calls come into play. I’m not 100% with them but I believe places that were liquidating sales (even robin hood) were doing it in good faith because margin calls mean stocks are bought on credit and the house would have taken the debt if they fell so couldn’t put themselves in that place.
I think the percentage value of a margin call relates to how much you have to put in to buy a stock - which is why we were hearing a lot about ‘margin calls are now 100% (or 0%)’ meaning either way, you needed the cash upfront to make a purchase.
