The specter of regional fragmentation in interest rate swap trading flows as a result of early implementation within the U.S. has long been looming.  While initial evidence supported the narrative that regulatory market structure changes have caused regional fragmentation in liquidity, recent data suggests that this trend may be abating- for now. In this TABB Group report, U.S. Swaps 2015 : Paradise Lost?, TABB Group looks at recent developments in the U.S. Interest Rate Swap market, market share and volume trends within the SEF trading landscape, and emerging liquidity dynamics between European and U.S. regulatory regimes.