25 USC 641 - Congressional findings and declaration of purpose

For the purpose of assisting in the economic advancement and contributing to the general welfare of the Hopi Indian Tribe of Arizona, the Congress hereby finds it to be fitting and appropriate to provide the Hopi Tribal Council with certain powers of self-determination that are necessary to enable the Hopi people to carry out the effective development and operation of the Hopi Industrial Park, which is located in the counties of Navajo and Coconino in the State of Arizona.

25 USC 642 - Powers of Tribal Council

The Hopi Tribal Council shall have the following powers:
(a) Sale of lands 
To sell any part of the lands within the Hopi Industrial Park.
(b) Mortgages or deeds of trust; law governing mortgage foreclosure or sale; United States as party; removal of cases; appeals 
To execute mortgages upon, or deeds of trust to, the lands within said Hopi Industrial Park. Such lands shall be subject to foreclosure or sale pursuant to the terms of such mortgage or deed to trust in accordance with the laws of the State of Arizona. The United States shall be an indispensable party to, and may be joined in, any such proceeding involving said lands with the right to remove the action to the United States district court for the district in which the land is situated, according to the procedure in section 1446 of title 28, and the United States shall have the right to appeal from any order of remand entered in such action.
(c) Pledge of revenue or other income to secure indebtedness for development of park; law governing action to enforce pledge; United States as party 
To pledge any revenue or other income from lands within said Hopi Industrial Park, and the improvements situated thereon, and any other revenue or income that may be available to the Hopi Tribe without regard to source, to secure any indebtedness of the Hopi Tribe incurred in the development of said Hopi Industrial Park, and any action to enforce said pledge shall be in accordance with the laws of the State of Arizona, and the United States shall be an indispensable party thereto to the same extent and under the same conditions as hereinbefore provided in the case of mortgage foreclosures.
(d) Issuance of bonds and payment of costs thereof; sale of bonds at public or private sale 
To issue bonds for and on behalf of the Hopi Tribe, and pay the costs thereof, to accomplish the purposes of this subchapter, in one or more series, in such denomination or denominations, maturing at such time or times, and in such amount or amounts, bearing interest at such rate or rates, in such form either coupon or registered, to be executed in such manner, payable in such medium of payment, at such place or places, subject to such terms of redemption, with or without premium, and containing such other restrictive terms as may be provided by tribal ordinance. Such bonds may be sold at not less than par at either public or private sale and shall be fully negotiable.
(e) Appointment of bank or trust company as trustee for purposes of authorization and creation of issue of bonds; authority to commence action to enforce obligations to tribe without joining United States as party 
To appoint a bank or trust company with its home office in the State of Arizona having an officially reported combined capital, surplus, undivided profits and reserves aggregating not less than $10,000,000 as trustee for all of the purposes provided in the ordinance authorizing and creating any issue of bonds. Any trustee so appointed may be authorized to commence an action for and on behalf of, or on relation of, the Hopi Tribe to enforce any obligation to the tribe pledged to secure payment of the bonds without joining the United States as a party thereto.
(f) Entering business ventures as shareholder, or as limited partner with corporation, firm or person operating within park 
To enter into any business venture as a shareholder of a corporation issuing nonassessable stock, or as a limited partner with any corporation, firm or person operating within said Hopi Industrial Park.
(g) Lease of lands and improvements thereon 
To lease lands within the Hopi Industrial Park, any other tribal lands, and the improvements thereon, in accordance with the provisions of Federal laws.

25 USC 643 - Councils powers subject to approval by Secretary

The exercise of all powers granted the Hopi Tribal Council by this subchapter shall be subject to the approval of the Secretary of the Interior, or his duly authorized representatives.

25 USC 644 - Bonds as valid and binding obligations

Bonds issued by authority of this subchapter and bearing the signatures of tribal officers in office on the date of the signing thereof shall be valid and binding obligations, not withstanding that before the delivery thereof and payment therefor any or all of the persons whose signatures appear thereon have ceased to be officers of the Hopi Tribal Council.

25 USC 645 - Exemption from taxation

All bonds issued by the Hopi Tribal Council for and on behalf of the Hopi Tribe and the interest provided in said bonds shall be exempt from taxation to the same extent they would have been exempt if the bonds had been issued by the State of Arizona or a political subdivision thereof.

25 USC 646 - Exempted securities

Any securities issued by the Hopi Tribal Council (including any guarantee by such council), and any securities guaranteed by the council as to both principal and interest, shall be deemed to be exempted securities within the meaning of sections 77c (a)(2) and 78e (a)(12) of title 15, and shall be exempt from all registration requirements of Acts of May 27, 1933, and June 6, 1934.