In plain terms. DTAR is the Department of the Treasury's supplement to the FAR, adding Treasury-specific contract rules.
Who it applies to. Contractors serving Treasury and its bureaus (such as the IRS).
What it requires. Meet the FAR, then DTAR additions. Treasury work frequently involves financial and taxpayer information, so expect strong privacy, safeguarding, and access-control requirements (including IRS rules where tax data is involved).
Why it matters. Financial and taxpayer data is highly sensitive and tightly regulated, making protection a core obligation on Treasury contracts.
Citation. DTAR, the Department of the Treasury Acquisition Regulation supplement to the Federal Acquisition Regulation (FAR), codified in the FAR System at Title 48 of the C.F.R.