Major MBS issuers are concerned about the potential harm evolving risk-retention regulations could have on securitization structures, regardless of which structure issuers decide to use. In response to the interagency proposed rule on credit risk retention, Citigroup said the public interest is not served by requiring securitizers to hold positions that are designed to take losses. “For example, all deal parties, the rating agencies and the investors are fully aware that the lowest tranche, sometimes referred to as a ‘first loss’ tranche, may take losses and no representation is made that such tranche is either investment grade or will receive...