[gruez]

>Is this where there was a problem? But the retail trading platform takes zero financial risk as long as they don't allow their customers to trade on credit (which is an entirely different issue).

From matt levine:

>This means that the seller takes two days of credit risk to the buyer. I see a stock trading at $400 on Monday, I push the button to buy it, I buy it from you at $400. On Tuesday the stock drops to $20. On Wednesday you show up with the stock that I bought on Monday, and you ask me for my $400. I am no longer super jazzed to give it to you. I might find a reason not to pay you. The reason might be that I’m bankrupt, from buying all that stock for $400 on Monday.

>Generally if you buy a stock on Monday you still want it on Wednesday; even if you don’t, we live in a society, and you’ll probably cough up the money anyway because that’s what you’re supposed to do. But at some level of volatility things break down. If a stock is really worth $400 on Monday and $20 on Wednesday, there is a risk that a lot of the people who bought it on Monday won’t show up with cash on Wednesday. Something very bad happened to them between Monday and Wednesday; some of them might not have made it. You need to make sure the collateral is sufficient to cover that risk. The more likely it is that a stock will go from $400 to $20, or $20 to $400 for that matter, the more collateral you need.

https://www.bloomberg.com/opinion/articles/2021-01-29/reddit...

[xorcist]

Yes, so I take it to mean that indeed the retail trading platform (the actual term may be something else), takes zero financial risk. The broker that the retail trading platform uses to access the trading exchange takes this risk.

But the counterparty risk here is quantifiable (by way of audits of said retail trading platform) which usually in society makes it a case for insurance, not security payments. That is my question. Is the premise misstated, and if not, why is this not settled by insurance?

The three replies posted to the question above seems to disagree what the problem actually was.

[bdonlan]

In the financial industry collateral is normally used as the primary means of mitigating counterparty risk as it avoids adding an additional counterparty that you then have to evaluate for creditworthiness, and you have to pay them money instead of just temporarily handing over collateral and getting it back 100% later on.

That being said the collateral doubles as a sort of insurance; if one party's collateral is insufficient to cover the loss, the excess is spread across other market participants. This is one reason why client funds can't be used for this collateral.