22 U.S.C. § 3307 - Exemption from taxation

(a) United States, State, or local taxes 
The Institute, its property, and its income are exempt from all taxation now or hereafter imposed by the United States (except to the extent that section 3310 (a)(3) of this title requires the imposition of taxes imposed under chapter 21 of title 26, relating to the Federal Insurance Contributions Act) or by any State or local taxing authority of the United States.

(b) Charitable contributions; transfers for public, charitable, and religious uses; charitable and similar gifts 
For purposes of title 26, the Institute shall be treated as an organization described in sections 170 (b)(1)(A), 170 (c), 2055 (a), 2106 (a)(2)(A), 2522 (a), and 2522 (b) of title 26.