Start with the contract, then map the payoff
The same option label can describe a different multiplier, premium unit and settlement process. Record those terms before using an expiry formula.
| Check | Write down | Why it changes the result |
|---|---|---|
| Contract | Underlying, symbol, expiry, exercise style | Determines the reference price and when the right is exercised |
| Units | Premium quote, multiplier, settlement currency | One quoted premium may apply to multiple underlying units |
| Position | Existing exposure and each long or short leg | A put, call or spread changes different parts of the payoff |
| Operations | Margin, fees, expiry fixing, partial fills | Expiry math alone omits path and account risk |
Build scenarios before choosing a story
- Freeze the venue specification and copy its source date.
- Calculate each leg in its native quote and settlement units.
- Map terminal prices below, between and above the strikes.
- Add the underlying, premiums, fees and execution costs.
- Mark Greeks, margin and pre-expiry value unknown unless separately modeled.