https://www.thestreet.com/story/11064384/1/kass-trade-the-ra...
This story happened more than a week ago, and GDAX has since (at great cost) decided to refund all those who lost money due to margin calls or stop loss orders: https://blog.gdax.com/eth-usd-trading-update-2-216a3b946ef6
Hopefully this will serve as an important lesson on the risks of margin trading, and encourage all exchanges to implement circuit breakers.
Sometimes these limits are 1/2x and 2x of average/opening/auction price, sometimes are very tight. Some exchanges stop trading given security for the day, others are recalculating these limits in almost real time and stop for a couple of minutes max.
All these safeguards are there for a reason. And some site positioning themselves as “exchange” and not reversing/pausing (or at least ivestigating) tells only about their maturity.
If Ethereum grows a few orders of magnitude, then they should probably stop trading the same reason the stock market does.
...allowing them to take advantage for a second time, possibly?
Of course in a regulated market that would be blatantly illegal.
Not knowing how an exchange works, they put the order in for sell 33300 ETH at market price to cash in their earnings and ride off into the sunset. The buy book wasn't thick enough to absorb that much sell side @ market, so the market sells and margin calls ate the entire buy down to the very bottom huge buy @ $0.10 each.
So did the value drop that low? Not really. Just due to a very immature and primitive market on one particular exchange, did this happen. When you compare these Crypto-exchanges to modern stock or forex exchanges, you'll see that they are just vastly less sophisticated.
GDAX tweet two days before the glitch: https://twitter.com/GDAX/status/876857569850998784