An inquiry for contract, side and amount directed to one or more dealers, auction-style. Historically, this trading protocol has been associated with OTC derivatives and lower levels of transparency but since October 2013 market participants have been using the RFQ protocol for trading on SEFs (see swap execution facilities). These platforms require that each request receives at least three responses with the objective of increased transparency. Many industry participants believe that the RFQ model is the only trading protocol suitable for traditional OTC products which are more bespoke in nature and highly structured. They argue that a standardised Central Limit Order Book (CLOB) model which is associated with listed derivatives would not work because there would not be enough liquidity or standardisation in either execution or the associated infrastructure. According to ISDA, a regulatory requirement which forces the industry to trade products on a model which is not suitable may render them worthless and shrink the market.