[grapehut]

Yeah, in reality it's not what happened. Exchanges don't instantly margin-call positions, they have to use time-outs and do it slowly (or there simply isn't going to be the liquidity).

So it's pretty easy to get the price of tether on a single exchange to momentarily hit $400, just blow through the order book. However no one is getting margin-called just yet, so the trick is to sustain that price, which means buying tether at $400 a piece. Unless you've got hundreds of millions of dollars to blow, it's simply not possible. And something as obvious as that, manual circuit breakers are going to be getting hit before they let margin calls cascade.