As a result, interest rates in sustainable microfinance institutions (MFIs) are substantially higher than the rates charged on normal bank loans. They argue that this policy will best insure the permanence and expansion of the services they provide. Sustainable (i.e., profitable) microfinance providers can continue to serve their clients without needing ongoing infusions of subsidies, and can fund exponential growth of services for new clients by tapping commercial sources such as deposits from the public.