The Commissioner of Housing shall establish and administer a program of grants, loans and deferred loans to housing development corporations which have qualified for state assistance under § 8-217, or to eligible developers, as defined in § 8-39, for the purpose of making loans, loan guarantees and interest subsidies in connection with the construction or rehabilitation of dwelling units for low and moderate income persons. Such grants, loans or deferred loans shall be made only to housing development corporations or eligible developers which have resources from the private sector equal to or greater than the amount of the proposed grant, loan or deferred loan. No loan, deferred loan, loan guarantee or interest subsidy shall derive more than fifty per cent of its funds from any state grant, loan or deferred loan. In the case of a deferred loan, the contract shall require that payments on all or a portion of the interest are due currently but that payments on principal may be made at a later time.