MCO 5216.20B - Marine Corps Supplement to SECNAV M-5216.5 Department of the Navy Correspondence Manual

Scope

MCO 5216.20B is the Marine Corps supplement to SECNAV M-5216.5, the Department of the Navy Correspondence Manual. The order operationalizes DON correspondence format rules at the Marine Corps level, format adjustments, signature authority delegations, by-direction signing rules, directives correspondence handling, and message procedures. Every Marine Corps unit drafts and signs correspondence applying both documents, the DON manual for format, this supplement for the Marine Corps layer.

Audience

• S-1 officers, chiefs, adjutants, and legal clerks producing official correspondence.
• By-direction signers and the commanders delegating signature authority.
• Directives Control Points and records managers filing what gets signed.

Operative content

• By-direction delegations die with the commander. At change of command the new commander re-issues every delegation letter under their own signature, predecessor delegations do not transfer.
• Signature delegations document on DD Form 577 alongside the appointment letters.
• Unit letterhead pulls from the Directives Control Point, paired with MCO 5215.1K.
• Congressional responses draft in naval letter format under SECNAVINST 5730.5 routing with this supplement's Marine Corps adjustments.
• MARADMIN message format follows the supplement's message handling procedures.

Content scope

Marine Corps naval letter format adjustments, signature authority delegations, by-direction signing rules, MCO directives correspondence handling, message format supplements, stationery and letterhead, and the Marine Corps SSIC usage cross-referenced to SECNAV M-5210.2.

Connection to higher policy

• SECNAV M-5216.5. The parent DON Correspondence Manual, naval letter at Chapter 1, endorsements at Chapter 2, signing and authenticating at Chapter 8, messages at Chapter 10.
• SECNAVINST 5730.5. Congressional inquiry response routing.

Connection to Marine Corps doctrine and lower policy

• MCO 5215.1K. The directives issuance system sharing the DCP and SSIC machinery.
• SECNAV M-5210.2. The SSIC codes every letter carries.
• MCO 5000.14D MCAP. The S-1 correspondence duties the supplement serves.

Status

Active with Admin Change 4, confirmed against MCPEL and the archived CH-4 PDF on 2026-07-15. The one portal citation referencing Admin Change 3 now reads CH-4. Two unreviewed import stubs for this order sit in _stubs pending consolidation into this entry.