GST ISD vs Cross-Charge: How to Handle Shared Services Across GSTINs

One head-office invoice, several GSTINs

A company pays for a common software subscription, audit service, or other input service at its head office. The service benefits multiple branches, each registered under the same PAN in a different State. The invoice is in one GSTIN’s name, but the related input tax credit may belong across more than one registration.

Since 1 April 2025, the law requires an office receiving input-service invoices for or on behalf of distinct persons to register as an Input Service Distributor (ISD) and distribute the credit under the prescribed rules. The amended definition also includes specified reverse-charge input-service invoices. That makes it important to distinguish credit distribution from a separate supply of services between registrations. See Section 20 of the CGST Act and Rule 39 of the CGST Rules.

ISD and cross-charge are not interchangeable labels

An ISD is a registered office that distributes eligible input tax credit on input services received for distinct persons under the same PAN. It issues the prescribed ISD document to pass the credit to the relevant registrations. It is a credit-distribution mechanism, not a general way to bill branches for every shared cost.

A cross-charge concerns a supply of services between distinct GST registrations of the same legal entity. For example, one registration may provide management, IT, or other support services to another. That transaction needs to be examined as a supply, including its taxability and valuation, on its own facts.

The practical distinction is the transaction being recorded. A third-party vendor invoice for a common input service raises the ISD distribution question. A service provided by one registration to another raises a cross-charge question. A business can have both kinds of activity, so one mechanism should not be used as a blanket substitute for the other.

What changed from 1 April 2025?

Before the amendment, businesses often discussed whether common input-service credit could be distributed through ISD or through cross-charge arrangements. The amended Section 20 now requires an office receiving the covered input-service invoices for or on behalf of distinct persons to register as an ISD and distribute the related credit.

The current text also includes input services subject to reverse charge under the relevant CGST and IGST provisions. Rule 39(1A) sets out a specific route for such credit: a registered person with the same PAN and State code as the ISD may transfer the credit to the ISD using the prescribed invoice or credit/debit note, after which the ISD distributes it under Rule 39. This is a detail to check carefully when the reverse-charge payment and ISD registration sit in different parts of a multi-GSTIN structure.

The requirement is about covered input services. It does not mean every shared expense, purchase of goods, or inter-office transaction automatically belongs in the ISD process. First establish what was supplied, who received the service, which GSTINs it relates to, and whether the credit is eligible.

How Rule 39 guides allocation

Rule 39 gives different treatment based on which registrations the service relates to:

If an input service is attributable to one recipient, distribute the credit only to that recipient.
If it is attributable to some, but not all, recipients, distribute it among those recipients on the prescribed pro-rata turnover basis.
If it is attributable to all recipients, distribute it among them on the prescribed pro-rata turnover basis.

The rule also requires eligible and ineligible credit to be distributed separately, and the credit available for distribution in a month is to be distributed in that month with the details reported in GSTR-6. The applicable turnover period and the complete Rule 39 conditions matter, so a simple headcount or equal split is not a safe default.

A review checklist for CA teams

Before closing the month, keep a short working paper for shared-service invoices:

Identify the actual supplier, service, invoice recipient, and GSTIN that received the invoice.
List the distinct registrations that benefit from the service and document why it is attributable to one, several, or all of them.
Check ITC eligibility and identify any ineligible portion before working out distribution.
Apply the relevant Rule 39 allocation basis, using the prescribed turnover period where pro-rata distribution is required.
For reverse-charge input services, verify the same-PAN and same-State-code route in Rule 39(1A), along with the supporting transfer document.
Issue the required ISD documents, reconcile the distribution to the source invoice, and include the details in the relevant GSTR-6.
Separately review any actual services supplied between registrations for cross-charge, taxability, and valuation requirements. Do not treat the vendor’s original invoice as an internal cross-charge merely because several branches benefit from it.

This trail helps explain the connection between the vendor invoice, the recipient registrations, and the credit reported by the ISD. Keep the allocation working, supporting invoices, and return records together for review.

The useful question is what happened

For a common third-party input service, ask how its eligible credit must be distributed under the ISD rules. For a service provided by one GST registration to another, separately examine whether a taxable cross-charge arises and how it should be valued. The labels are not a shortcut around identifying the underlying transaction.

Invozen does not calculate Rule 39 ISD allocations, generate ISD documents, or prepare or file GSTR-6. This article is general GST guidance, not an Invozen filing workflow. Review the current law and the facts of each arrangement with a qualified GST professional before reporting or distributing credit.