HMRC: 4,000+ Tranche-One Applications as MMTAR Tranche Two Opens

HMRC’s 18 August 2026 press release confirms that more than 4,000 applications were submitted and over 2,000 accounts created during the first Modernising and Mandating Tax Adviser Registration (MMTAR) window. That window closed on 18 August. As of 19 August, tranche two is open through 18 November 2026 for advisers who hold a Self Assessment or Corporation Tax agent account but still lack an Agent Services Account (ASA).

Robert Jones, HMRC’s Director of Intermediaries, framed the programme as reinforcing trust and transparency across the tax advice market. Registration remains free and online. Advisers who missed tranche one, or who are new entrants, should register as soon as possible — HMRC states that submitting an application and receiving a registration number lets you continue engaging with HMRC while the application is processed, and short-term access to online services is not cut off solely because processing is incomplete.

Who must act in the 18 August–18 November window

Tranche two covers advisers with a Self Assessment or Corporation Tax account who do not have an ASA. Payroll-only firms sit in a later window (18 November 2026 to 18 February 2027). Financial services organisations follow from 31 December 2026 to 31 March 2027. Use HMRC’s interactive checker rather than assuming a sister office’s ASA covers every agent ID.

Tax advisers who already have an ASA do not re-register in this phase. HMRC will move existing ASA holders to the new digital service by 31 March 2027 and will contact them through the account if further information is required.

What happens if you miss the window

HMRC may limit an adviser’s ability to act for clients if they fail to register when required. Advisers who continue to operate without completing the registration requirement could also face enforcement action, including financial penalties. That is why tranche-two firms should treat the three-month window as a hard evidence and application timetable, not a soft start.

Keep agent MFA workstreams separate: voluntary MFA activation for the 19 August cohort is live today, and remaining accounts flip automatically between 28 September and 15 October. Do not let MFA troubleshooting stall ASA packs.

Action checklist for tranche-two firms

Confirm every agent ID against HMRC’s checker and name an owner for each ASA application.

Assemble identity evidence, AML supervision status, supervisory body details, and ownership information before partners invent lists under client pressure.

Open the ASA application early so HMRC processing time does not collide with autumn MFA automatic activation.

Missed tranche-one firms and new entrants should register now rather than waiting for a later cohort that may not apply.

How FinnAccountings helps while registration beds in

Clean client ledgers reduce pressure when partners spend August and September on ASA applications. FinnAccountings helps Ireland and UK advisers and business owners prepare bookkeeping and tax packs with Chartered Accountant insight before you or your ICAEW/ACCA or Chartered Accountant (Ireland) adviser files. Start a free trial for review-ready drafts — we prepare records; we do not register you with HMRC or file agent applications on your behalf.

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Related reading

Day-three tranche-two briefing keeps the November close in view as applications continue.

MMTAR tranche two: day three checklist →

Use this morning’s day-one tranche-two briefing for the handover narrative after 18 August.

MMTAR tranche two: day one after 18 August →

Keep the weekend tranche-two checklist beside the application form.

MMTAR tranche-two weekend checklist →

Pair registration work with today’s MFA activation checklist if any IDs opted in by 31 July.

HMRC agent MFA activates 19 August →

Payroll-only firms should start ASA evidence packs before their 18 November window opens.

MMTAR payroll-only prep before 18 November →