Any cash settled future is going to have to have a reference rate. The Brent Index is an example for a certain type of crude oil: https://en.wikipedia.org/wiki/

Any cash settled future is going to have to have a reference rate. The Brent Index is an example for a certain type of crude oil: https://en.wikipedia.org/wiki/Brent_Crude#Brent_Index https://en.wikipedia.org/wiki/Brent_Crude#Brent_Index