Investors will be able to exchange existing Freddie Mac participation certificates for new single securities when the GSE creates new “mirror” securities to help facilitate the transition.The exchange program will be available when the new single security goes live and Freddie plans to keep it open for the foreseeable future. Held in a Federal Reserve account, the mirror securities will not increase the outstanding principal balance of Freddie MBS, the GSE explained in an update on the exchange program. The mirror securities will track existing Freddie MBS but substitute a 55-day payment cycle for Freddie’s current 45-day cycle. Freddie will pay compensation equal to the fair market value of the 10 days of lost float when...