The single most important operational question for multi-location businesses under GST is this: which costs are common expenses that must be routed through the Input Service Distributor, and which are directly attributable to a specific GSTIN? Getting this classification wrong triggers ITC denial, penalty exposure, and audit objections. With the ISD mechanism becoming mandatory from 1st April 2025, the classification exercise has moved from being a compliance optimisation to a legal necessity.
This article provides a practical framework for classifying costs and implementing the ISD and cross-charge mechanisms correctly.
The Legal Framework
Under Section 25(4) of the CGST Act, 2017, establishments of the same person in different states are treated as distinct persons. When the Head Office (HO) receives an invoice for a service that benefits multiple branches, the ITC cannot simply be claimed at the HO. It must be distributed to the branches that actually consume the service.
Two mechanisms exist:
- ISD: For distributing ITC on common input services received from third-party vendors.
- Cross-Charge: For supplies of goods or services between distinct persons, including internally generated services.
From 1st April 2025, ISD registration is mandatory for any registered person having multiple GST registrations. The CBIC notification dated 6th August 2024 (Notification No. 16/2024-Central Tax) formally removed the optionality that previously existed.
What Are Common Expenses?
Common expenses are costs incurred at a centralized location (typically the HO or corporate office) that benefit or are attributable to more than one GST registration. Typical examples include:
- Enterprise software licences and SaaS subscriptions.
- Group-wide audit and professional fees.
- Corporate advertising and brand campaigns.
- Nationwide insurance policies.
- Centralized IT infrastructure and cloud hosting.
- HR and recruitment services for multiple locations.
These expenses must be routed through the ISD mechanism. The ISD receives the invoice, records the ITC in its books, and issues ISD invoices to each beneficiary branch based on the turnover ratio.
What Are Directly Attributable Expenses?
Directly attributable expenses are costs that exclusively benefit a single GST registration. These are not routed through the ISD. Examples include:
- Branch-specific office rent.
- Local utility bills.
- State-specific marketing campaigns.
- Regional employee salaries and benefits.
- Local vendor invoices addressed directly to the branch GSTIN.
These expenses are claimed directly by the respective branch in its GSTR-3B.
The Internally Generated Services Distinction
A critical distinction exists between externally procured common services and internally generated services. Internally generated services — such as centralised management, accounting, or IT support provided by the HO to its branches — are supplies between distinct persons. These are handled through the cross-charge mechanism, not the ISD.
The TaxGuru analysis clarifies this distinction: ISD is fundamentally a mechanism for distribution of ITC on input services received from external vendors, while cross-charge concerns supplies of goods or services between distinct persons.
The Turnover Ratio Method
Under Rule 39 of the CGST Rules, ITC available for distribution through ISD is allocated on a monthly basis to each distinct person in the same proportion as the turnover of that person in the preceding financial year bears to the aggregate turnover of all distinct persons.
The formula is:
ITC to be distributed to Branch A = Total Common ITC × (Turnover of Branch A / Aggregate Turnover of All Branches)
The ISD must issue ISD invoices to each branch and file GSTR-6 by the 13th of the following month.
Valuation for Cross-Charge
Where the HO cross-charges internally generated services to branches, the value must be determined under Rule 28. The second proviso to Rule 28(1) provides that where the recipient branch is eligible for full ITC, the invoice value declared by the HO is deemed to be the open market value. The CBIC Circular No. 199/11/2023-GST clarifies that the HO may issue a nil-value invoice in such cases.
Practical Implementation Steps
- Assess every common expense: Determine whether it benefits one or multiple GSTINs.
- Establish clear classification guidelines: Document the criteria for ISD vs direct attribution.
- Obtain ISD registration: Apply in Form GST REG-01 with the ISD flag.
- Update ERP systems: Route vendor invoices to the correct GSTIN and set up ISD ledgers.
- Communicate with vendors: Ensure they invoice the correct entity.
- File GSTR-6 monthly: Report all distributions by the 13th.
- Maintain documentation: Retain ISD invoices, distribution workings, and GSTR-6 filings.
Consequences of Misclassification
- ITC denial: If common expenses are claimed directly at the HO without ISD distribution, the ITC is at risk of denial.
- Penalty under Section 122: Incorrect ITC claims attract penalty of 100% of the tax or ₹10,000, whichever is higher.
- Interest: 18% interest on ITC wrongly utilised.
- Audit objections: The departmental auditor will specifically examine the ISD classification.
Conclusion
The ISD mandate from April 2025 has made cost classification a critical compliance exercise. Businesses with multiple GST registrations must classify every expense as either common (ISD) or directly attributable (direct claim), implement the turnover-ratio distribution mechanism, and file GSTR-6 monthly. Getting this wrong invites ITC denial and penalty.
At Anuj Desai & Associates, we provide expert advisory services on ISD implementation, cost classification, and cross-charge structuring for multi-location businesses. Our team can help you transition smoothly to the mandatory ISD regime.
For a confidential consultation, contact us at office@anujdesaiassociates.com or call 9619456656. Visit our website at https://anujdesaiassociates.com or connect with our founder on LinkedIn at linkedin.com/in/ca-anuj-desai-122547230.