The UK commodities and financial futures markets have long been recognised as significant contributors to UK invisible earnings. Their contribution has not, however, been measured reliably for more than ten years. Against a background of large, positive balancing items in the balance of payments over the last few years, indicating the existence of unidentified net inflows in either current or capital accounts, a programme of work is in hand to improve the quality of balance of payments statistics. One part of this has been to carry out an enquiry to measure the extent of invisible earnings by these markets. This article describes the enquiry's findings.