The first futures contract launched by the London-based International Petroleum Exchange (IPE) in 1981. It has evolved into a benchmark for spot middle distillate oil across northwest Europe. In the United States, gas oil is often referred to as heating oil. The contract is traded on the IPE floor using open outcry trading. Physical delivery for the contract occurs near Amsterdam, Rotterdam, and Antwerp; however, most contract users employ the contract as a financial mechanism to protect against losses and close out their positions before they have to deliver or receive the gas oil. The options contract is based on the underlying IPE futures contract.