Compliance
Singapore’s Estates & Trusts Tax Reference Number Overhaul: What Executors Must Know
Singapore’s IRAS is changing the tax reference numbers for estates, trusts, and unit trusts—from 10-character ITR IDs to new 9-character ASGD IDs. Here’s what to prepare before January 2027.
By NomadicTax Research Team • 5-8 min read • August 24, 2026
## What’s Changing
Starting **July 2026**, the **Inland Revenue Authority of Singapore (IRAS)** began phasing in a new 9-character tax reference number format (“ASGD ID”, like *AXXXXXXXX*) for **Estates, Trusts and Unit Trusts**, replacing the older 10-character ITR IDs (e.g. 3000123456/330012345X). ([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 rollout includes:
- Progressive notifications to executors, trustees, and legal personal representatives.
- Dual use of ITR IDs temporarily during system upgrades through **December 2026**.
- As of **January 2027**, **all tax notices** will use only the **ASGD 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))
## Why It Matters
- All **payments**, standing instructions, and official documents must use the new ASGD ID by **January 2027**.
- Legacy ITR IDs will no longer be accepted after December 2026.
- Misquoting IDs can cause processing delays, mismatches, or even rejection of notices.
## What Executors & Trustees Should Do Now
- Upon receiving the new ASGD ID, update **bank details, standing instructions**, and any third-party forms or agreements to reflect it.
- Check legal documents, wills, fiduciary contracts that reference ITR ID and plan amendments if needed.
- Tax agents handling estates/trusts should obtain the ASGD ID from each client promptly, or request replacement if notice lost. Email trust@iras.gov.sg as required.
- Track system upgrades—IRAS is upgrading digital services, including e-filing for Forms T and UT starting early 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))
## Example Scenario
*Estate of Mr. Lee*: Executor gets notice in August 2026 showing both ITR ID and new ASGD ID. They set up their accounting and payment systems to use ASGD immediately. In November, an asset sales document mistakenly quotes the ITR ID—this could trigger mismatch with IRAS system after December. Executor corrects document and re-issues with ASGD. Tax filing for YA 2027 uses only ASGD.
## Key Takeaways
- The change is administrative, meant to improve security and efficiency under IRAS digital systems.
- Transition period allows dual recognition but ends **31 December 2026**.
- Awareness and timely updates are essential to avoid operational hiccups in estate/trust tax affairs.