Non-QM loans include mortgages that do not meet Qualified Mortgage standards due to factors such as alternative income documentation (bank statement loans), debt service coverage ratio underwriting (DSCR loans for investors), interest-only payment structures, pricing above QM thresholds, or sale to private securitizers rather than government-sponsored enterprises. For analytical purposes, Polygon Research also flags business-purpose and DSCR loans separately within the Non-QM category.