Fee per Contract
Fee per contract is a fixed charge per contract (often per side). It scales linearly with the number of contracts traded.
Definition
Fee per contract is a fixed fee charged for each contract traded. Platforms may charge it per side (entry and exit separately).
Why it matters
Per contract fees can be a large fraction of the price range in prediction markets. They are especially important when trading small price edges, because the fee does not shrink with spread.
How to incorporate it
• Compute effective spread from fills and midquote.
• Add fee per contract to compute all in cost for entry or round trip.
Common pitfalls
Forgetting round trip: If you pay on both entry and exit, total fees double.
Mixing units: Make sure fee units match your price scale (0 to 1 vs cents).