Leading secondary-market representatives told the Financial Industry Regulatory Authority they generally support its goal of mitigating the counterparty credit risk borne by participants in the “to be announced” market and reducing the potential for systemic risk. But they are opposed to FINRA’s proposal to require maintenance margin to attain that aim – something the Treasury Market Practices Group has already considered and rejected. Issued back in January, FINRA’s proposed amendments stipulated that for bilateral transactions in covered agency securities with non-exempt accounts, FINRA members must collect, in addition to variation margin, maintenance margin equal to 2 percent of the market value of the securities. If sufficient margin is not collected, the member would have to deduct the uncollected amount from the member’s net capital at the close of business following the business day on which the deficiency was created. Additionally, if the deficiency in margin is not resolved...