The Housing Assistance Corporation (HAC) is a subsidiary of NYC Housing Development Corporation (HDC). HAC can receive money from any source (including HDC or New York City government agencies) to assist rental developments in maintaining rents that are affordable to low- and moderate-income residents. HAC is not, however, authorized to issue bonds or notes. Instead HAC can transfer, lend, pledge, or assign money to any rental development. It also can assist HDC in financing developments. In order to implement its initiatives, HAC enters into a Tenant Assistance Contract (TAC) with mortgagors to provide monthly rental assistance payments. To be eligible for TAC payments, the mortgagor must ensure that 20 percent of the developments rental units are available for households whose annual income at initial occupancy does not exceed 80 percent of New York City median income as adjusted for family size, and 80 percent of the rental units are available for households whose annual income at initial occupancy does not exceed 180 percent of New York City median income.