The rating on the California School Finance Authority's (CSFA) series 2023A and 2023B charter school revenue bonds, issued for STEM Preparatory Schools' obligated group, is 'BBB-'. The outlook is stable. The bonds are secured by gross revenues of the obligated group, which includes two of the network's three schools, STEM Preparatory Elementary School and Math and Science College Preparatory (MSCP). The network's third school, Crown Preparatory Academy (CPA), is not included in the obligated group and its revenues are not pledged to the bonds. The bonds are further secured by a debt service reserve fund that is funded at maximum annual debt service (MADS) with grant proceeds from the CSFA Credit Enhancement Grant Program. Based on our group rating methodology,