Except as otherwise provided in subsection (c) of section 10a-237, the authority may invest any funds in (1) direct obligations of the United States or the state of Connecticut, (2) obligations as to which the timely payment of principal and interest is fully guaranteed by the United States or the state of Connecticut, and Connecticut’s Short-Term Investment Fund, (3) obligations of the United States Export-Import Bank, Farmers Home Administration, Federal Financing Bank, Federal Housing Administration, General Services Administration, United States Maritime Administration, United States Department of Housing and Urban Development, Farm Credit System, Resolution Funding Corporation, federal intermediate credit banks, federal banks for cooperatives, federal land bank, federal home loan banks, Federal National Mortgage Association, Government National Mortgage Association and the Student Loan Marketing Association, (4) certificates of deposit or time deposits constituting direct obligations of any bank in the state, provided that investments may be made only in those certificates of deposit or time deposits in banks which are insured by the Federal Deposit Insurance Corporation if then in existence, (5) withdrawable capital accounts or deposits of federal chartered savings and loan associations which are insured by the Federal Savings and Loan Insurance Corporation, (6) other obligations which are legal investments for savings banks in the state, (7) investment agreements with financial institutions whose long-term obligations are rated within the top two rating categories of any nationally recognized rating service or of any rating service recognized by the Banking Commissioner or whose short-term obligations are rated within the top two rating categories of any nationally recognized rating service or of any rating service recognized by the Banking Commissioner, or investment agreements fully secured by obligations of, or guaranteed by, the United States or agencies or instrumentalities of the United States, and (8) securities or obligations which are legal investments for savings banks in Connecticut, subject to repurchase agreements in the manner in which such agreements are negotiated in sales of securities in the market place, provided the authority shall not enter into any such agreement with any securities dealer or bank acting as a securities dealer unless such dealer or bank is included in the list of primary dealers, as prepared by the Federal Reserve Bank of New York, effective at the time of the agreement. Any such securities may be purchased at the offering or market price thereof at the time of such purchase. All such securities so purchased shall mature or be redeemable on a date or dates prior to the time when, in the judgment of the authority, the funds so invested will be required for expenditure. The express judgment of the authority as to the time when any funds shall be required for expenditure or be redeemable is final and conclusive.