Sensitive But Unclassified
) is a designation of information in the United States Federal Government
that, though unclassified, often requires strict controls
over its distribution. SBU is a broad category of information including For Official Use Only
), Law Enforcement Sensitive (LES), Sensitive Homeland Security
Information, Security Sensitive Information (SSI), Critical Infrastructure Information (CII), etc. Some categories of SBU information have authority in statute or regulation (e.g. SSI, CII) while others (FOUO) do not. "FOUO" is primarily a Department of Defense phrase/acronym. Other government departments use it, but many have also come up with their own, similar phrases, to include "Sensitive but Unclassified".
Information that may be classified with these labels range from personally identifying information such as passport and Social Security numbers to documents protected by the attorney-client privilege. Though SBU information may be exempt from complete disclosure under the Freedom of Information Act, it should not be universally withheld.