Hong Kong’s Inland Revenue Department (IRD) announced on 26 October 2026 that new functions for top-up tax return filing are live under the Pillar Two Portal. For overseas directors and finance teams that hold Hong Kong entities inside an in-scope multinational enterprise (MNE) group, this is the practical switch from “regime announced” to “returns can be filed electronically”.
This page summarises publicly available IRD materials only. It is not tax advice, does not decide whether your group is in scope, and does not replace the Notes and Instructions to the return or advice from a qualified tax representative.
What launched on 26 October 2026
Per the IRD’s What’s New notice and the dedicated GMT / HKMTT webpage:
- A Part 4AA entity of an in-scope MNE group for a fiscal year beginning on or after 1 January 2025 can now file a top-up tax return through the Pillar Two Portal.
- Filers can also view and download notices of top-up tax assessment electronically.
- The IRD has updated guidance materials (including user guides) for filing.
The electronic return form is commonly referred to as BIR82 (Top-up Tax Return). According to the IRD, the return covers information needed for Hong Kong minimum top-up tax (HKMTT), income inclusion rule (IIR) top-up tax, and — when the relevant provisions commence — undertaxed profits rule (UTPR) top-up tax. Where the GloBE Information Return (GIR) is filed in Hong Kong, it forms part of the top-up tax return.
Who typically needs to file
At a high level, IRD materials describe filing entities of an in-scope MNE group as including Hong Kong constituent entities, certain Hong Kong joint-venture entities, and specified Part 4AA “stateless” entities created or operating in Hong Kong. Exact coverage depends on the legislation and your group facts — confirm with your advisors; do not treat this summary as a scope determination.
Hong Kong also allows the group to designate one Hong Kong constituent entity (a designated local entity) to file the top-up tax return for the reporting fiscal year so that other Hong Kong constituent entities of the same group are relieved from filing that return for that year. Appointment is annual and must follow IRD rules.
Filing deadlines (high level)
Per IRD FAQs and the published guide to filing the Top-up Tax Return:
- Ordinary deadline: 15 months after the end of the reporting fiscal year.
- Transition year for filing purposes: extended to 18 months after the end of that fiscal year (determined at MNE group level under IRD rules).
Example (illustrative only): for a calendar-year 2025 reporting fiscal year, the ordinary 15-month mark falls around 31 March 2027. Always calculate from your year end and confirm transition-year status with your tax representative.
E-filing only — prepare access early
IRD states that the top-up tax return must be filed electronically through the Pillar Two Portal; paper filing is not accepted. Access is typically via the Business Tax Portal (BTP) or Tax Representative Portal (TRP), with authorised Pillar Two Portal user roles (for example notifying entity, service provider, or persons responsible for management, as described in IRD user guides).
Practical preparation for overseas owners often includes:
- Confirming whether any Hong Kong entity sits inside an in-scope MNE group for fiscal years beginning on or after 1 January 2025.
- Agreeing who is the designated local entity (if used) and who holds portal credentials.
- Aligning accounting close, GloBE / HKMTT computations, and GIR data-file testing with the portal timeline.
- Coordinating Hong Kong statutory accounts and audit timelines with group Pillar Two workstreams — see also our overview of Hong Kong audit requirements and Hong Kong accounting & audit services.
Practical takeaways for overseas directors
- Treat 26 Oct 2026 as the go-live for return filing on the portal — notifications and related functions may already have existed; return filing is the new milestone.
- Do not invent a single due date for every entity — use 15 / 18 months from the reporting fiscal year end, then verify transition-year treatment.
- Budget time for portal setup (BTP/TRP access, certificates, service-provider appointments) well before the statutory deadline.
- Keep Profits Tax and Pillar Two tracks separate but coordinated — for example, Accounting Date Code “M” block extensions for Profits Tax (useful for March year-end / 3月年結 companies) do not by themselves change Pillar Two return deadlines. See our note on the 2025/26 ‘M’ code extension.
- Read the primary IRD pages before instructing agents; secondary summaries can lag behind portal updates.
Sources
Primary sources (please read the originals; this page only summarises):
- IRD — What’s New (26 October 2026): launch of top-up tax return filing under the Pillar Two Portal
- IRD — Global minimum tax and Hong Kong minimum top-up tax for MNE groups
- IRD — FAQs on the Pillar Two Portal
- IRD — A guide to file Top-up Tax Return (PDF, 10/2026)
Need help coordinating Hong Kong accounting, audit calendars, or compliance questions for an overseas-held Hong Kong company that may sit in a larger group structure? Send an enquiry with your year end and entity type.
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