Revenue received through federal, state and local cash grants or reimbursements to fulfill operating expense obligations not covered by fares or other revenues generated by the transit system.

Paid to social housing providers built under historic housing programs and guaranteed for the life of the mortgage (usually 25 years) to bridge the gap between revenue from market rents and the total cost of mortgage and operations. Under the Social Housing Reform Act, this subsidy pays for the "unaffordable mortgage". Over the next 30 years, the obligations of government to fund this social housing will gradually expire, housing provider by housing provider as mortgages are paid off.

Subsidy paid by the federal government to a local housing authority to compensate for the limitation on rent of 30% of a tenant's adjusted monthly income; a result of the Housing and Urban Development Act of 1970. The operating subsidy funds-the amount of the deficit between rents and expenses up to the difference between the annual contributions paid the authority by the federal government.