Hey - so let me answer in two parts. First by showing you this link and the below image, and secondly by giving a more detailed overview of the associated charges on this. The detailed example of overnight charges is a little dated (with the oil price) but should still provide clarity.  https://www.ig.com/uk/commodities    Let me know if I have misinterpreted your question...      1) The formula for calculating the Overnight Basis Adjustment is as follows:  Overnight Basis = (P3 – P2)/