An off-the-peg suit is cheaper than a bespoke suit but is unlikely to fit as well, while a bespoke suit may look beautiful but there will be a tight limit to how many a tailor can produce. So tailors, keen to make more suits but keep their customers happy, have developed the "made-to-measure" concept: the suit is made to a set pattern, using the customer's own measurements. In the world of derivatives a similar development is taking place.

Over-the-counter derivatives are so named because each is designed to suit the particular needs of counterparties. "An OTC derivative is a contract between two parties," says Hans Hufschmid, chief executive of GlobeOp Financial Services, which provides technology solutions for the middle and back office. "Each counterparty and each contract has unique details."