The authority is hereby authorized and empowered to invest any funds not needed for immediate disbursement in any of the following securities:
(1) Direct obligations of or obligations guaranteed by the United States of America;
(2) Bonds, debentures, notes or other evidences of indebtedness issued by any of the following agencies: Banks for cooperatives; federal intermediate credit banks; federal home loan bank system; Export-Import Bank of the United States; federal land banks; the Federal National Mortgage Association or the Government National Mortgage Association;
(3) Public housing bonds issued by public agencies or municipalities and fully secured as to the payment of both principal and interest by a pledge of annual contributions under an annual contributions contract or contracts with the United States of America; or temporary notes issued by public agencies or municipalities or preliminary loan notes issued by public agencies or municipalities, in each case, fully secured as to the payment of both principal and interest by a requisition or payment agreement with the United States of America;
(4) Certificates of deposit secured by obligations of the United States of America;
(5) Direct obligations of or obligations guaranteed by the State of West Virginia;
(6) Direct and general obligations of any other state within the territorial United States, to the payment of the principal of and interest on which the full faith and credit of such state is pledged: Provided, That at the time of their purchase, such obligations are rated in either of the two highest rating categories by a nationally recognized bond-rating agency; and
(7) Any fixed interest bond, note or debenture of any corporations organized and operating within the United States: Provided, That such corporation shall have a minimum net worth of $15 million and its securities or its parent corporation's securities are listed on one or more of the national stock exchanges: Provided, however, That (i) such corporation has earned a profit in eight of the preceding ten fiscal years as reflected in its statements, and (ii) such corporation has not defaulted in the payment of principal or interest on any of its outstanding funded indebtedness during its preceding ten fiscal years, and (iii) the bonds, notes or debentures of such corporation to be purchased are rated "AA" or the equivalent thereof or better than "AA" or the equivalent thereof at least two or more nationally recognized rating services such as Standard and Poor's, Dun & Bradstreet or Moody's.