Which one of the following four features is NOT a typical characteristic of futures contracts?

Futures contracts have several key characteristics that differentiate them from other types of financial instruments. The features include a fixed notional amount per contract, fixed dates for delivery, and daily margin calls to manage credit risk. Futures are standardized contracts traded on exchanges, not over-the-counter (OTC). OTC trading typically refers to securities or derivatives that are not listed on formal exchanges and are traded directly between parties, which is not a feature of futures contracts.