Earlier quoted context omitted.
If so, why doesn’t this happen all the time? In fact, when has it EVER happened before, or since? If it was normal wouldn’t there regularly be stocks that can’t be bought but can be sold?
Because stocks valuations don't jump by 2000%, with volumes up 3000% 'all the time'. And when they do, they aren't solely driven by retail investor mania pig-piling the exact same brokerage. And, uh, particular brokerages have stopped uni-directional trades for volatile stocks in the past, for the exact same reason. You may notice that no retail brokerage makes any guarantees to its customers that they will be able t…
My understanding is that Robinhood is self-clearing, not that Citadel is its prime brokerage.
The clearing margin requirement came from NSCC. Clearing margins CANNOT be satisfied using client funds. So it’s Robinhood’s own capital—and whatever credit lines they’ve negotiated—that would need to meet those requirements.
If I deposit 100k into Robinhood and keep it there as cash for 2 years, then one day I plunk all of it into GME, then until all my trades settle two days later, Robinhood will have increased clearing margin requirements based on the VaR of my unsettled trades. (Unless, my trade offsets someone else’s from within Robinhood, in which case I believe RH’s margin would reduce—but I’m not sure about this part.)
And if one day after my trades, GME’s stock goes up 10x, the VaR goes up roughly 10x as well. Even though I would have a claim to a lot higher value in my account once everything is settled, until the trades are settled, it’s a major cash crunch for RH.
The fact of the matter is that RH was not under-capitalized or have disproportionately small credit lines as a portion of their AUM, as compared to other brokerages. It’s just that their users were the ones that acted in a most coordinated way on a stock whose VaR was going through the roof.