In this comprehensive report, the C1 Subcommittee summarizes their work on collateralized loan obligations (CLO) modeling work completed over the past several years. The report begins with the basics of CLOs and describes the modeling approach, data universes, and assumptions and methodology. The report identifies the final C-1 factors and portfolio adjustment factors. Finally, the report summarizes reconciliation of the proposed model with proposed CLO C-1 factors as well as limitations and areas for future work.