25 C.F.R. § 1000.1125
How does the Department acknowledge receipt of final offer?
(a) Within 10 days of receipt by the officials designated by the Secretary in § 1000.1110, the Department will send the Tribe/Consortium a written acknowledgement of the final offer.
(b) The acknowledgement reference in paragraph (a) of this section shall include:
(1) A statement acknowledging receipt of the final offer;
(2) The date the final offer was received and the last day of the applicable statutory review period;
(3) If applicable, the Secretary may request additional information. A request for more information has no effect on deadlines for a response under this subpart; and
(4) A statement notifying the Tribe/Consortium that technical assistance is available upon request to comply with paragraph (b)(3) of this section.