Earlier this year, the CFTC required that swap execution facilities (SEFs) with temporary SEF registration status come into full compliance with all applicable SEF rules beginning on October 2, 2013. Originally, those rules were thought to apply only to transactions that would be required to trade on a SEF. However, the language of the rule’s Footnote 88 implies that rules would apply to any transaction the SEF offered, whether or not that transaction is mandated to trade on a SEF. These concerns prompted ISDA to conduct a SEF Market Fragmentation Survey to obtain a clear picture of potential market disruption or fragmentation resulting from SEF rule implementation. This Research Note examines the results of that survey.