# Marking Spreads When calculating mark or prior\_mark for any spread product, we use the best available data in this order: 1. If a user supplies a product in the trade's **MARK** field (i.e. forwards, swaps), the mark for that Product. This includes copies if **MARKET DATA COPY** is turned on 2. If the Mark field is not filled out (i.e. futures), the mark for the trade's Product 3. If the above aren't present (and we have a **spread\_formula**), we attempt to use the **spread\_formula** to resolve the mark 4. If none of these are available or if we are using the **spread\_formula** to resolve the mark, and one of the marks in the formula is not available, we do not mark the trade If you upload forward marks for a spread and want that product to settle against a spread formula, the product will settle against the forward marks.