Compliance
Singapore Changes Tax Reference Numbers for Estates and Trusts Ahead of Digital Upgrade
From July 2026, IRAS is issuing new ASGD IDs for estates, trusts and unit trusts to streamline digital services from 2027; here's what executors and trustees need to know.
By NomadicTax Research Team • 5-8 min read • August 11, 2026
## Overview
Singapore’s tax authority (IRAS) has introduced a significant administrative change: **from July 2026**, active estates, trusts, and unit trusts will receive new **tax reference numbers** in the **ASGD ID** format (one letter ‘A’ plus eight digits). The old **ITR ID** (10 characters, example: 3000123456) will be phased out for these entities starting **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))
## What This Means in Practice
* Executors, administrators, legal personal representatives, trustees, and tax agents should watch for notifications from IRAS—these will contain their new ASGD IDs.([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 standing instructions, tax notices, payment records, or authorisation documents referencing the old ITR IDs should be updated once the ASGD ID is issued. During the transition period (between notification and December 2026), IRAS will still accept payments that quote the old ITR ID and match them to the correct entity.([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))
## Action Steps
1. **Check for IRAS notification**: ensure you receive or locate the letter/email issuing your ASGD ID.
2. **Update all documents and systems**: payments, internal accounting, invoicing, legal documents that reference the tax ID.
3. **Coordinate with your tax agent (if applicable)**: tax agents may request ASGD IDs using IRAS’s portal if their client has not yet informed them.([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))
4. **Verify only ASGD ID for new documents after Jan 2027**: from that point forward, tax notices will exclusively show ASGD IDs. Old ITR IDs will no longer be used.([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))
## Implications and Benefits
* **Digital readiness**: new IDs support upcoming digital enhancements and services in IRAS’s income tax e-filing systems for these types of entities.([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))
* **Security and standardisation**: shorter, standardised IDs help reduce errors, simplify record keeping, and improve system interoperability.
* **Compliance risk if not updated**: outdated documents may lead to mismatches or payment delays if they still refer to the old ID past the transition.
## Example Scenario Comparisons
| Scenario | Before (Using ITR ID) | After Issue of ASGD ID (Transition Period) | After Jan 2027 (Mandatory Use) |
|---|---|---|---|
| Executor paying tax | Uses old ITR ID | Either ITR or ASGD accepted | Must use ASGD only |
| Structure paying royalties or distributions | Old ITR ID for notices/forms | Update to ASGD, old still recognised | ASGD mandatory |
## Recommended Timeline
- **July–Dec 2026**: transition period. Update systems and documents as soon as the ASGD ID is received.
- **By Jan 1, 2027**: ASGD IDs fully adopted for all communications and transactions.
**Bottom line**: If you’re an executor, trustee, or tax agent working with estates, trusts, or unit trusts in Singapore, prioritise transitioning to the new ASGD ID format—ensure all systems and payment records are aligned before 2027 to avoid disruption.