In late December, issuers of new non-agency MBS will become subject to new risk-retention requirements. It’s not clear whether anyone will notice. The vast majority of loans securitized in jumbo MBS over the past few years meet the qualified-mortgage standard. And because federal regulators opted to synchronize the QM standard with the separate qualified residential-mortgage standard, jumbo MBS backed entirely by QMs will be exempt from the 5 percent risk-retention requirement. When the final rule came out, Redwood Trust backed...