La. Stat. tit. 39 § 1452
All refunding bonds issued pursuant to this Chapter shall be and are hereby made negotiable instruments within the meaning of and for all purposes of the negotiable instruments law of Louisiana, subject only to the provisions of the refunding bonds for registration. All refunding bonds and the income therefrom shall be exempt from all taxation by this state or any political subdivision thereof. The refunding bonds shall be legal and authorized investments for banks, savings banks, insurance companies, homestead and building loan associations, trustees and other fiduciaries and may be used for deposit with any officer, board, municipality or other political subdivision of the state of Louisiana, in any case where, by present or future laws, deposit or security is required.
La. R.S. § 39:1452