Input Service Distributor: When Head Office Costs Need Structured Distribution
A post-April-2025 operating guide for ISD registration, vendor invoicing, attribution, rule 39 distribution, RCM common services, GSTR-6 and recipient credit.
ISD is now a core group-GST process, not a year-end allocation entry. Common service invoices must be identified when received.
The amended section 20 and rules make the ISD mechanism applicable from 1 April 2025 for its covered common input-service scope.
ISD deals with input services received by one office for or on behalf of distinct persons.
Credit attributable to one recipient should be distributed only to that recipient; common credit uses the prescribed turnover-based method.
Eligible and ineligible credit, as well as tax heads, should be distributed separately.
What the business should understand
- The amended section 20 and rules make the ISD mechanism applicable from 1 April 2025 for its covered common input-service scope.
- ISD deals with input services received by one office for or on behalf of distinct persons.
- Credit attributable to one recipient should be distributed only to that recipient; common credit uses the prescribed turnover-based method.
- Eligible and ineligible credit, as well as tax heads, should be distributed separately.
- Specified common services on which tax is paid under reverse charge are included in the amended ISD framework.
The five-point review
| Check | What to examine |
|---|---|
| Registration | ISD GSTIN and portal access. |
| Vendor invoice | Correct recipient and common-service nature. |
| Attribution | Direct recipient or multiple recipients. |
| Distribution | Turnover base, tax head and eligible/ineligible status. |
| Return | GSTR-6, ISD documents and recipient 2B/credit. |
Practical example
A software licence covers four GST registrations, but the vendor invoices the normal head-office GSTIN and finance claims the full credit there. From April 2025, the covered common input-service credit should be routed through the ISD framework rather than left with the head office.
How to apply the framework
Update procurement instructions so vendors use the ISD GSTIN for covered common services. Build a workflow to transfer legacy or incorrectly addressed invoices only through a legally supportable correction.
Reconcile the monthly ISD pool from vendor invoice to GSTR-6 and recipient 2B. Differences should be fixed before recipient GSTR-3B filing.
Decision workflow
Define the legal question before changing the return
Identify the GSTIN, tax period, transaction, document and exact statutory question. Review registration, vendor invoice and attribution together. Freeze the source data so that later ERP edits do not destroy the evidence used for the decision.
Reconcile from commercial reality to portal data
Start with the contract or commercial event. Move through the invoice, receipt or movement evidence, e-invoice or e-way bill, accounting entry, return and electronic ledger. Classify each difference as timing, error, ineligible amount, statutory exception, disputed position or completed correction. Avoid a plug entry whose only purpose is to make two reports equal.
Record the conclusion and future control
Prepare a concise position note with facts, authority, amount, alternative view and approval. Preserve the filing acknowledgement and update the responsible master data, vendor rule, invoice workflow or monthly checklist. The objective is not only to survive one review but to prevent the same issue in the next period.
Action checklist
- Maintain ISD registration.
- Define covered service categories.
- Direct vendors to the correct GSTIN.
- Attribute and distribute monthly.
- File GSTR-6 accurately.
- Reconcile recipient credit.
Evidence to keep
- ISD registration
- Vendor master and invoices
- Recipient/turnover matrix
- ISD invoices/credit notes
- GSTR-6 and recipient 2B
Warning signs
- ISD started only at year end
- Vendor invoices normal GSTIN without review
- Capital goods distributed through ISD
- All credit treated eligible
- Recipient turnover base undocumented
Finin2min takeaway
GST positions are strongest when the transaction, legal provision, invoice, physical or service evidence, books, return and electronic ledger agree. A portal match without commercial evidence is not a complete control.