Net Interest Margin Securities (NIMS) A type of security that allows holders to access excess cash flows resulting from securitized mortgage loan pools. Investopedia Says: Excess cash flows from the securitized mortgage loan pools are transferred to a trust account through a NIMS transaction. From this trust account, investors of the NIMS receive interest payments. Related Terms: Collateral Collateralized Mortgage Obligation Commercial Mortgage Backed Securities Mortgage Backed Securities Structured Finance |