The preliminary ratings assigned by S&P Global Ratings to the prime floating-rate residential mortgage-backed securities (RMBS) to be issued by Perpetual Trustee Co. Ltd. as trustee for Series 2023-1 Harvey Trust reflect the following factors. The credit risk of the underlying collateral portfolio (discussed in more detail under "Credit Assessment") and the credit support provided to each class of rated notes are commensurate with the ratings assigned. Credit support is provided by subordination and lenders' mortgage insurance (LMI) and excess spread, if any. Our assessment of credit risk takes into account Great Southern Bank's (GSB; a business name of Credit Union Australia Ltd.) underwriting standards and approval process, which are consistent with industry-wide practices; the servicing quality of GSB (discussed