Section 12
SEC. 12. Exemption from tax.&mdashThe Authority shall be exempt from all taxes incidental to its operations: Provided, That its subsidiary corporations shall be subject to all said taxes five years after their establishment under a graduated scale as follows: twenty per centum, of all said taxes during the sixth year, forty per centum of all said taxes during the seventh year, sixty per centum of all said taxes during the eighth year, eighty per centum of all said taxes during the ninth year, .and one hundred per centum of all said taxes during the tenth year; after said establishment. Such exemption shall include any tax or fee imposed by the government on the sale, purchase or transfer of foreign exchange. All notes, bonds and debentures and other obligations issued by the Authority shall be exempt from all taxes, both as to principal and interest, except inheritance and gift taxes.