Basel III capital requirements proposed by federal regulators will have a significant negative impact on U.S. bank holdings of agency and non-agency MBS, according to industry participants. The capital requirements have yet to be finalized and are currently scheduled to begin being phased in Jan. 1 with full implementation in 2018. In June, the Federal Deposit Insurance Corp., the Federal Reserve and the Office of the Comptroller of the Currency proposed rules to implement Basel III capital standards – the most comprehensive overhaul of the U.S. bank capital framework since Basel I was implemented in 1989. Comments were due last week, and strong warnings were submitted by trade groups representing MBS market participants, banks and mortgage lenders. “If the Basel III [proposed rule] were implemented...