25 CFR 227.26: Assignments and overriding royalties.

(a) Leases, or any interest therein, may be assigned or transferred only with the approval of the Secretary of the Interior, and to procure such approval the assignee must be qualified to hold such lease under existing rules and regulations, and shall furnish a satisfactory bond for the faithful performance of the covenants and conditions thereof. No lease or any interest therein, or the use of such lease, shall be assigned, sublet, or transferred directly or indirectly, by working or drilling contract, or otherwise without the consent of the Secretary of the Interior. Assignments of leases shall be filed with the superintendent within 20 days after the date of execution.

(b) An agreement creating overriding royalties or payments out of production under this part shall be subject to the provisions of § 211.26(d) of this chapter, or as hereafter amended.