The state treasurer, upon order of the state board of finance, shall invest the proceeds of state revenue and general obligation bonds until the money is needed for the purpose for which the bonds were authorized and sold. Income from these investments shall be applied to payment of principal of and interest on the bonds, for the purposes for which the bonds were issued or to pay rebate, penalty, interest and other obligations of the state relating to the bonds under the Internal Revenue Code of 1986, as amended, including any regulations applicable under the code.