25 U.S. Code § 3306 - Limitations on use of funds
None of the funds made available under this subchapter may be used for study at any school or department of divinity or for any religious worship or sectarian activity.
No interest or other income on any funds made available under this subchapter shall be used for any purpose other than those for which such funds may be used.
Notwithstanding any other provision of law, any interest or investment income that accrues on any funds provided under this subchapter after such funds are paid to the Indian tribe or tribal organization and before such funds are expended for the purpose for which such funds were provided under this subchapter shall be the property of the Indian tribe or tribal organization and shall not be taken into account by any officer or employee of the Federal Government in determining whether to provide assistance, or the amount of assistance, under any provision of Federal law.
For the purposes of under recovery and over recovery determinations by any Federal agency for any other funds, from whatever source derived, funds received under this subchapter shall not be taken into consideration.