J.P. Morgan Mortgage Trust 2021-INV3's issuance is an RMBS transaction backed by first-lien, fixed-rate, fully amortizing investment property mortgage loans secured by one- to four-family residential properties, condominiums, and planned-unit developments to primarily prime borrowers. We assigned our ratings to 12 classes of mortgage pass-through certificates. The ratings reflect our view of the transaction's high-quality collateral, available credit enhancement, geographic concentration, and associated structural mechanics, among other factors. NEW YORK (S&P Global Ratings) July 30, 2021--S&P Global Ratings today assigned its ratings to J.P. Morgan Mortgage Trust 2021-INV3's mortgage pass-through certificates (see list). The certificate issuance is an RMBS securitization backed by first-lien, fixed-rate, fully amortizing investment property mortgage loans secured by one- to four-family residential properties, condominiums, and planned-unit