Compliance
Trusts and Estates in Singapore: New Tax Reference Numbers and What Trustees Should Know
Singapore’s IRAS is revamping tax reference numbers for trusts and estates to support its digital modernization—trustees and agents need to understand the switch before deadlines at year-end.
By NomadicTax Research Team • 5-8 min read • August 21, 2026
## What’s New? ASGD ID for Estates, Trusts, and Unit Trusts
From **July 2026**, the Inland Revenue Authority of Singapore (IRAS) is replacing the old **ITR ID system** (10-character numbers like 3000123456) with a new **9-character “ASGD ID”** format (AXXXXXXXX). This applies to estates, trusts, and unit trusts when filing **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))
IRAS will progressively notify trustees, executors, and legal personal representatives who need to file these forms. Note: some tax notices may still display old ITR IDs while systems are upgraded—expect full switchover by **January 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))
## Why This Matters
- Aligns with IRAS’s broader plan to launch enhanced digital services in **2027**. Improved digital security and taxpayer experience are driving the change. ([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))
- Delays or confusion may arise if you rely on the old ITR ID—not uncommon during transitions.
## What Executors, Trustees, and Agents Should Do Now
- **Watch your mail:** IRAS will send notices with your new ASGD ID. Don’t rely on the old number once you receive ASGD.
- **Update your records:** Legal documents, trust agreements, accounting software, and templates that reference tax reference numbers should be updated.
- **File correctly:** When filing Form T or Form UT, use ASGD ID where requested. If your notification is lost, you can request ASGD via the provided IRAS link (go.gov.sg/trustidrequest) between **August to December 2026**. ([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))
- **Expect some overlap:** Some notices may still display ITR ID until systems fully migrate at year-end. Keep both IDs in your documentation but prioritize ASGD.
## Example Situations
- A trustee preparing Form UT in November 2026 receives a notification letter with ASGD ID and files accordingly. If the printed tax notice still shows ITR ID, they should retain the notice for records but rely on ASGD for all filings.
- An executor who lost their notification letter can send a request via IRAS's link during the **August-December 2026** window. Without the request, there’s risk of misfiling or mismatch.
## Broader Implications & Tips
- Legal and accounting practitioners working with estates/trusts should alert their clients now; old tax reference numbers will gradually phase out.
- Digital tax systems require precise identifiers—mismatches could delay processing or trigger requests for clarification.
- Better security: ASGD IDs support better verification and fewer opportunities for identity mistakes or fraud.
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Transition periods are always messy, but the earlier you align, the smoother filing becomes in 2027 and beyond. Review your trust/estate client portfolios now, update identifiers, and ensure all digital systems are ready.