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Definition

CUI Marking

Also known as: CUI banner marking, CUI designation indicator

A CUI marking is the standardized label, at minimum the banner CUI or CONTROLLED at the top of each page, that identifies a document as Controlled Unclassified Information. The authorized holder who creates the document is responsible for applying CUI markings and dissemination instructions at the time of creation.

In more detail

The banner line can carry three parts: the control marking (CUI or CONTROLLED), category markings (for example CUI//SP-CTI), and limited dissemination controls. A designation indicator block identifies the designating agency.

Responsibility follows the creator, not the recipient: whoever originates CUI marks it. Recipients must protect marked CUI and preserve markings on any copies or derivatives, but they do not invent markings for unmarked information; if something arrives that seems sensitive but unmarked, the move is to ask the sender, not to mark it yourself.

Marking is also the bright line in the regulation: if a document carries no CUI banner, it is not CUI in the regulatory sense. For contractors this is the fastest scoping check available, unmarked ordinary contract information is FCI, which is CMMC Level 1 territory.

Primary source
NARA, CUI Marking Handbook

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