Possible Clues:

• Fiscal watchdog of the U.S. Congress
• U.S. auditor
• Fed. agcy. staffed with number crunchers
• Fed. fiscal watchdog
• Arm of the U.S. Cong
• US auditing agency
• Org. headed by the U.S. Comptroller General
• Agcy. concerned with the federal fiscal outlook
• Investigative arm of Congress
• Federal auditing agcy