Memorandum For The Heads Of Executive Departments And Agencies

On May 9, 2008 President Bush issued a Memorandum designating a "Controlled Unclassified Information" -- or "CUI" -- as the single executive-branch wide categorical designation for all terrorism-related information that was previously referred to as Sensitive But Unclassified (SBU).

http://www.whitehouse.gov/news/releases/2008/05/20080509-6.html