(a) The commission shall be responsible for the proper application of the proceeds of public debt issued under this article to the purposes for which it is incurred; provided, however, that the proceeds from guaranteed revenue obligations shall be paid to the issuer thereof, and the proceeds and the application thereof shall be the responsibility of the issuer.

(b) Proceeds received from the sale of bonds evidencing general obligation debt shall be held in trust by the commission and disbursed promptly by the commission in accordance with the original purpose set forth in the authorization of the General Assembly and in accordance with rules and regulations established by the commission. Bond proceeds and other proceeds held by the commission shall be as fully invested as is practical, consistent with the proper application of such proceeds for the purposes intended. Investments shall be limited to general obligations of the United States or of subsidiary corporations of the United States government fully guaranteed by such government, or to obligations issued by the Federal Land Bank, Federal Home Loan Bank, Federal Intermediate Credit Bank, Bank for Cooperatives, Federal Farm Credit Banks regulated by the Farm Credit Administration, Federal Home Loan Mortgage Corporation, Federal National Mortgage Association, or to tax exempt obligations issued by any state, county, municipal corporation, district, or political subdivision, or civil division or public instrumentality of any such government or unit of such government, or to prime bankers' acceptances, or to the units of any unit investment trusts the assets of which are exclusively invested in obligations of the type described in this subsection, or to the shares of any mutual fund the investments of which are limited to securities of the type described in this subsection and distributions from which are treated for federal income tax purposes in the same manner as the interest on said obligations, provided that at the time of investment such obligations or the obligations held by any such unit investment trust or the obligations held or to be acquired by any such mutual fund are limited to obligations which are rated within one of the top two rating categories of any nationally recognized rating service or any rating service recognized by the commissioner of banking and finance, and no others, or to securities lending transactions involving securities of the type described in this subsection. Income earned on any such investments or otherwise earned by the commission shall be retained by the commission and used to purchase and retire any public debt or any bonds or obligations issued by any public agency, public corporation, or authority which are secured by a contract to which the second paragraph of Article IX, Section VI, Paragraph I(a) of the Constitution of Georgia of 1976 is applicable and may be used to pay operating expenses of the commission. However, in order to provide for contingencies, efficiency, and flexibility, the commission may agree by contract or grant agreement with county and independent school systems that income earned during grant administration on a direct appropriation of state funds to the commission for public school capital outlay will be applied to the capital outlay purposes of the appropriation. Otherwise, the interest on direct appropriations to the commission shall be deposited into the treasury.

(c) Notwithstanding subsections (a) and (b) of this Code section, the Georgia Environmental Finance Authority shall be the state authority responsible for the proper application of the proceeds of public debt issued under this article for the purpose of making loans to counties, municipal corporations, political subdivisions, local authorities, and other local governmental entities for water or sewerage facilities or systems. Proceeds from the sale of such bonds shall be paid to the authority, which shall hold them in trust for their original purposes as set forth in the authorization of the General Assembly, as provided by law and in accordance with the rules and regulations established by the authority. Bond proceeds held by the authority shall be as fully invested as is practicable, consistent with the proper application of such proceeds for the purposes intended, and the authority shall contract with the Georgia State Financing and Investment Commission for the purpose of investing any such bond proceeds and the income therefrom. Investments shall be limited to those permitted to the authority or the Georgia State Financing and Investment Commission in the laws providing for their creation and activities. Income earned on any such investments of bond proceeds or the income therefrom shall be retained by the authority and used by it for its public purposes as provided by law.