MBS backed by multifamily mortgage loans would be exempt from a proposed rule that would establish margining requirements for multifamily agency finance. Had it been implemented as originally proposed, the rule would have amended the Financial Industry Regulatory Authority’s Rule 4210 to establish margin requirements in the single-family “to-be-announced” (TBA) market. At the same time, it would have also scoped in the multifamily housing programs of Fannie Mae and FHA/Ginnie Mae, according to the Mortgage Bankers Association. FINRA filed...