no you can't execute this order in retail accounts, check the volume. assignment risks would be off the charts.
Schwab would have allowed me to place that order, in that particular example.
You are correct that in some cases, the broker's risk management algorithm will stop an order if there is a high risk of assignment.
I've attached a screenshot of a credit spread that was rejected. In this example, the order is only 500 contracts, and with strikes that are two dollars apart, the max loss is supposedly only $100K.
But if I get assigned on the short leg and the long leg is out of the money, then I have to sell short 50,000 shares of SPY, and that's about $24 million of stock that I would be short overnight, and of course the broker is not going to allow that to happen.
But in my previous example, that kind of risk is not there. In the previous example, if the short leg expires in the money, then that means the long leg is
also in the money, and the two legs get exercised simultaneously, so the position simply dissolves, in that example at the max profit.
In my previous example, there
is a risk that the stock could close on expiration between the two strikes, and that would supposedly trigger automatic exercise of the long leg, requring the purchase of 750,000 shares of SPY, and that is obviously not within the capacity of the account.
But that is not a risk of
assignment. It is a risk associated with
automatic exercise. Exercise and
assignment are often used interchangeably, but they are not the same thing. Assignment is something that
happens to you. Exercise is something that
you do.
If you don't have the funds to exercise, then the broker is relieved of their duty to automatically exercise an ITM option. This, I believe, is why Schwab would allow the order in my first example. The broker has no exposure.
You have to monitor that kind of position on the day of expiration, because if you don't have the funds to exercise, your ITM option will expire without being exercised. In that situation, you have to close both legs before expiration.
Whack jobs on Reddit make these kinds of bets all the time. Remember that guy on Robinhood who killed himself because he thought he lost $700K, because they were only displaying the outcome of one leg of his position overnight?
DTE is one of the variables in the brokers' algorithms. If the strikes are far out-of-the money with a lot of time to expiration, the risk tolerance is higher.