...S&P Global Ratings assigned its 'A-1+' short-term rating to Massachusetts Housing Finance Agency's (MassHousing) roughly $100 million series 2021 single-family housing notes from within its single-family housing revenue bond (SFHRB) program and affirmed its ratings on the SFHRB's existing debt. The outlook on the long-term ratings is stable. The series 2021 notes will mature on Dec. 1, 2022, with an optional redemption on or after May 1, 2022. MassHousing is issuing these notes as a strategy to preserve the volume cap that would otherwise expire in 2021. It will deposit the proceeds of this issue into the resolution's purchase account and hold them in investments, as allowed under the resolution. It will apply any note proceeds not required to pay series 2021 note principal to the purchase of new mortgage-backed securities (MBS) and whole loans, including downpayment-assistance loans, only after the issuance of refunding bonds at or prior to Dec. 1, 2022, which will provide permanent financing...