Suppose I naked short a thousand deep out of the money puts for $3, and suppose they're extremely illiquid, with a usual bid of $1 and an ask of $5. The margin formula uses the put price, but doesn't define it. I can think of a lot of ways they could define the price of the put, and it matters a lot which one they use:
1. The last trade price
2. The ask price
3. Halfway between bid and ask
4. Black-Scholes price
5. Something else.
1. The last trade price
2. The ask price
3. Halfway between bid and ask
4. Black-Scholes price
5. Something else.
