The social welfare fund and all accretions thereto shall be deposited in the state treasury, as a separate and distinct fund, to the credit of the commissioner of human services as trustee for the beneficiaries thereof in proportion to their several interests. The commissioner of management and budget shall be responsible only to the commissioner of human services for the sum total of the fund, and shall have no duties nor direct obligations toward the beneficiaries thereof individually. Subject to the rules of the commissioner of human services money so received by a local social services agency may be deposited by the executive secretary of the local social services agency in a local bank carrying federal deposit insurance, designated by the local social services agency for this purpose. The amount of such deposit in each such bank at any one time shall not exceed the amount protected by federal deposit insurance.