Enterprise risk & controls · Working
Third line
Also called: third line of defence
ELI5
Independent assurance, commonly internal audit, over governance and controls.
Used in conversation
“The board will ask what happens if third line moves outside tolerance.”
Pitch context
You will see “Third line” in board papers, contracts, policies, risk registers and compliance reports when the discussion reaches enterprise risk & controls.
Why it matters: In enterprise risk & controls, a loose definition can change rights, obligations, approval, disclosure or enforceability.
Caution
Meaning, enforceability and required process vary by jurisdiction and agreement; this definition is not legal advice.
Sources & evidence · 3
Direct term-level sources and supporting source families.
- OECD — G20/OECD Principles of Corporate Governance 2023Direct source · institutional · checked 2026-08-16
- National Institute of Standards and Technology — Computer Security Resource Center GlossaryDirect source · primary · checked 2026-08-16
- U.S. Securities and Exchange Commission — EDGAR and filing resourcesSupporting source family · primary · checked 2026-08-16