Mapping your compliance footprint: registrations, distinct persons, ISD and a return-obligation matrix for every GSTIN

If your business has one PAN but operates from more than one state, the GST system does not see one business: it sees a separate taxpayer for every GSTIN, each with its own returns, credit ledger, due dates and notices. Most compliance failures in growing MSMEs start with an incomplete map: a godown nobody added to the registration, a branch that "is too small for e-invoicing", or a head-office bill whose credit really belongs to another state. Before you tighten returns or reconciliations, you need an exact picture of what you are registered for, where, and who is answerable for each filing.

What you need to know

Each GSTIN is a distinct person. GST registration is state-wise. When you supply from more than one state, each state registration is treated as a distinct person under the law, even though the PAN is the same. Two consequences follow. First, goods or services moving between your own GSTINs, such as a stock transfer from a Pune factory to a Bengaluru depot, are generally treated as supplies even without consideration, so they need tax invoices and a defensible value (lesson 11 covers this). Second, credit sitting in one GSTIN's electronic credit ledger cannot be used to pay tax in another.

Principal and additional places of business. Every location from which you do business within a state (factory, warehouse, godown, branch office, a unit taken on rent for festive stock, a third-party warehouse holding your goods) must appear on that state's registration, either as the principal place or as an additional place. Goods found at an undeclared location during an inspection are hard to explain, and the burden of explaining falls on you. Adding a place is an amendment application on the GST portal.

Core and non-core amendments. Changes to core fields (legal name, principal and additional places of business, partners, directors or similar responsible persons) go to the proper officer for approval; changes to non-core fields such as contact details are generally self-approved. The registration rules require you to apply within a short window after the change (15 days at the time of writing; confirm the current rule on the GST portal). Make it a process rule: signing a lease for a new godown triggers a registration amendment the same week.

Aggregate turnover is tested at PAN level. Several obligations depend on aggregate turnover, which is computed across all GSTINs under the same PAN: whether you must e-invoice, whether you may opt for the quarterly QRMP scheme, whether GSTR-9C applies, and how often you file ITC-04 for job work. A small branch GSTIN does not get a lighter regime because its own sales are small. Test each threshold against the PAN-level figure and confirm current limits on the GST portal and in CBIC notifications.

Common services and Input Service Distribution. Head-office costs such as statutory audit fees, ERP subscriptions, brand advertising or legal retainers are often billed to one GSTIN but benefit all of them. An Input Service Distributor (ISD) registration lets the head office receive such invoices and distribute the credit to the units that use the services, in the proportion the rules prescribe (broadly, the turnover of the recipient units in the relevant period). The law was amended so that, from April 2025, distributing credit for such common input services through ISD is required where the conditions apply. Whether and how it applies to your structure is a decision to take with your CA.

The obligation matrix. For each GSTIN, list every recurring filing and its frequency: GSTR-1 (monthly, or quarterly with the optional IFF under QRMP), GSTR-3B (monthly, or quarterly with PMT-06 payments under QRMP), GSTR-9 and, where applicable, GSTR-9C, ITC-04 if you send goods for job work, GSTR-6 for an ISD registration, and GSTR-7 or GSTR-8 if you are a TDS deductor or an e-commerce operator. Then add event-driven obligations: an IRN for every B2B invoice if e-invoicing applies, an e-way bill for every qualifying movement, and the annual Letter of Undertaking if you export without paying IGST.

Ownership, not just due dates. A calendar tells you when; a matrix tells you who. For every obligation name a preparer, a reviewer and a filer (the person whose DSC or EVC signs), and the folder where evidence is kept. When the only person holding the portal login leaves, a calendar does not help you.

Registration hygiene. Confirm for each GSTIN that the status is Active, bank account details are updated, Aadhaar authentication is complete where required, the registration certificate and GSTIN are displayed at each place of business, and the business activities and HSN/SAC codes on the registration reflect what you sell today.

This lesson is education, not tax advice; structural decisions such as additional registrations and ISD should be confirmed with a qualified CA or GST practitioner.

Step-by-step method

1. List every legal entity (PAN) in your group and every GSTIN under each PAN. Download each registration certificate from the GST portal.
2. Walk your physical footprint: every factory, godown, office, depot and third-party warehouse where your goods sit. Mark each against a GSTIN and against the principal or additional places shown on the certificate.
3. Draw the flows between GSTINs: stock transfers, shared staff, shared services and head-office recharges. Each arrow is a potential taxable supply.
4. Calculate PAN-level aggregate turnover for the last three financial years and test each threshold-based obligation against it.
5. Build the obligation matrix: rows are obligations, columns are GSTINs, cells show frequency and due date.
6. For each cell, name a preparer, reviewer and filer, and record where the evidence is stored.
7. List pending amendments (new locations, changed partners or directors, new business lines) and file them.
8. Identify common services billed centrally and decide, with your CA, how that credit will be distributed.
9. Save the matrix in a shared sheet with a change log and review it every quarter, or immediately after any change in location, turnover band or business line.

Common mistakes

• Adding a new warehouse to operations but not to the registration, so stock found there looks unaccounted.
• Testing e-invoicing, QRMP or GSTR-9C applicability against one GSTIN's turnover instead of PAN-level aggregate turnover.
• Keeping all head-office credit in one GSTIN when the services benefit other states, leaving one ledger over-credited and the others under-credited.
• Treating movements between your own GSTINs as internal book entries with no invoice or tax.
• Letting one employee hold every portal login and DSC with no documented handover or backup filer.
• Building the matrix once and never updating it after new locations, product lines or a change in turnover band.

Ask the AI Business Tutor

• "My business is a [entity type] with PAN-level aggregate turnover of about ₹[amount], operating from [locations and states] and selling [products or services]. List the GST registrations and additional places of business I should have, every recurring return for each GSTIN, which obligations depend on aggregate turnover, and the questions I should ask my CA about distributing credit for [common services billed to head office]."