Compliance
How Singapore’s ASGD IDs Are Transforming Tax Reference Numbers for Trusts and Estates
Singapore’s IRAS is switching over to ASGD IDs for estates, trusts and unit trusts. Discover what this means and how to prepare.
By NomadicTax Research Team • 5-8 min read • August 12, 2026
## What’s Changing
From **July 2026**, IRAS will begin transitioning estates, trustees, and unit trusts to a new tax reference format: **ASGD ID** (format `AXXXXXXXX`). The old format — the 10-character ITR ID (e.g., `3000123456` or `330012345X`) — will be phased out. This change is rolling out gradually and is part of IRAS’ push to support new digital services launching in **2027**. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
## Who’s Affected
- Executors, administrators, legal personal representatives, and trustees who are required to file **Form T** or **Form UT**. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
- Any existing tax agents working on behalf of these entities; your records will need updating too. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
## What You Need to Do Now
- Once notified by IRAS of the ASGD ID, start using it for all filings, enquiries, and payments — even during the transition. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
- Update internal systems, templates, forms, accounting records to use ASGD ID instead of ITR ID. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
- If you appointed a tax agent, share the ASGD ID with them so everything is kept consistent. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
- Register or appoint a **Corppass Administrator** by **31 December 2026**, ideally ahead of using the upcoming e‐Filing services in 2027. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
## The Big Picture: Why It Matters
- It supports **IRAS’ digital services** rollout which will offer e-Filing for estates, trusts, and unit trusts through myTax Portal in 2027. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
- Strengthens **security** in tax administration and ensures consistency in reference numbers. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
- Helps prevent mismatches: even during the transition (July–December 2026), IRAS will match old ITR IDs for payments submitted to them while systems are being updated. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
## Example Scenario
> You’re the administrator of a trust that files **Form UT** annually. Your ITR ID was `3000123456`. In August 2026, IRAS sends you a notification that your trust’s new ASGD ID is `A12345678`.
>
> **Starting immediately**, you:
> - Use `A12345678` on all correspondence to IRAS.
> - Update your accounting software and any internal templates to show the new ID.
> - Provide this ASGD ID to your solicitor or tax agent.
> - Register a Corppass Administrator by **31 Dec 2026** to use upcoming digital services. At payments or filings during this year, IRAS will still accept ITR ID where necessary; after January 2027, only ASGD IDs are valid. ([iras.gov.sg](https://www.iras.gov.sg/taxes/other-taxes/trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts/change-of-tax-reference-numbers-for-estates--trusts--unit-trusts?utm_source=openai))
If you manage an estate, trust or unit trust, double check whether you’ve been notified of an ASGD ID yet; if not, reach out to IRAS to avoid delays when digital services go live in 2027.