14 U.S.C. § 2121

(a) When the report of a board convened to recommend officers for promotion has been approved by the President, the Secretary shall place the names of all officers selected and approved on a list of selectees in the order of their seniority on the active duty promotion list. The names of all officers approved by the President and recommended by the board to be placed at the top of the list of selectees shall be placed at the top of the list of selectees in the order of seniority on the active duty promotion list. (b) Officers on the list of selectees may be promoted by appointment in the next higher grade to fill vacancies in the authorized active duty strength of the grade as determined under section 2103 of this title after officers on any previous list of selectees for that grade have been promoted. Officers shall be promoted in the order that their names appear on the list of selectees. The date of rank of an officer promoted under this subsection shall be the date of his appointment in that grade. (c) An officer serving on active duty in the grade of ensign may, if found fully qualified for promotion in accordance with regulations prescribed by the Secretary, be promoted to the grade of lieutenant (junior grade) by appointment after he has completed twelve months’ active service in grade. The date of rank of an officer promoted under this subsection shall be the date of his appointment in the grade of lieutenant (junior grade) as specified by the Secretary. (d) When a vacancy in the grade of rear admiral occurs, the senior rear admiral (lower half) serving on the active duty promotion list shall be appointed by the President, by and with the advice and consent of the Senate, to fill the vacancy. The appointment shall be effective on the date the vacancy occurred. (e) Appointments of regular officers under this section shall be made by the President, by and with the advice and consent of the Senate except that advice and consent is not required for appointments under this section in the grade of lieutenant (junior grade) or lieutenant. Appointments of Reserve officers shall be made as prescribed in section 12203 of title 10 . (f) (1) The promotion of an officer may be delayed without prejudice if any of the following applies: (A) The officer is under investigation or proceedings of a court-martial or a board of officers are pending against the officer. (B) A criminal proceeding in a Federal or State court is pending against the officer. (C) The Secretary determines that credible information of an adverse nature, including a substantiated adverse finding or conclusion described in section 2115(a)(3), with respect to the officer will result in the convening of a special selection review board under section 2120a of this title to review the officer and recommend whether the recommendation for promotion of the officer should be sustained. (2) (A) Subject to subparagraph (B), a promotion may be delayed under this subsection until, as applicable— (i) the completion of the investigation or proceedings described in subparagraph (A); (ii) a final decision in the proceeding described in subparagraph (B) is issued; or (iii) the special selection review board convened under section 2120a of this title issues recommendations with respect to the officer. (B) Unless the Secretary determines that a further delay is necessary in the public interest, a promotion may not be delayed under this subsection for more than one year after the date the officer would otherwise have been promoted. (3) An officer whose promotion is delayed under this subsection and who is subsequently promoted shall be given the date of rank and position on the active duty promotion list in the grade to which promoted that he would have held had his promotion not been so delayed.