Seller's Call

A seller's call is a futures contract where the seller gets to pick the time to set the price. It comes up in commodities trading.

The price isn't included in the original call contract when it's first written. Instead, the price will be set at some point in the future. A seller's call puts the onus on the contract's seller. There's also the opposite situation, known as the buyer's call, where the responsibility goes to the buyer of the contract.