Section 40 of CGST Act 2017 — First Return

Section 40 of CGST explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.

Section 40 of the CGST Act, 2017 provides that every registered person who becomes liable to register must declare, in the first return furnished after grant of registration, the outward supplies made during the period from the date they became liable to registration till the date registration was granted. This ensures no taxable supply escapes reporting during the gap between liability and actual registration.

What Section 40 Says — In Plain English

Section 40 addresses a very practical timing problem built into the GST registration system. A person often crosses the registration threshold (or otherwise becomes liable) on one date, but the GSTIN is granted only a few days or weeks later after the application is processed and verified. During that interval the person is already legally liable to charge and pay tax on outward supplies, yet has no live GSTIN and therefore no return in which to report them. Left unaddressed, this would create a permanent blind spot where genuine taxable turnover simply falls through the cracks.

The section resolves this by requiring that the very first return filed after registration (through the normal Forms GSTR-1 and GSTR-3B, once the GSTIN is active) capture the outward supplies made from the date of becoming liable to register right up to the date registration is granted. In plain terms: your first return is not just about the days after your GSTIN went live — it must also sweep in the interim period so that the Government receives tax on everything you sold from the moment your liability began. This dovetails with Section 25, under which an application filed within 30 days of becoming liable makes the registration effective from the date of liability itself.

Clause / Sub-section Breakdown

Applicability & Scope

• Applies to a person who crosses the aggregate turnover threshold and becomes liable to register under Section 22.
• Applies to persons liable to register compulsorily under Section 24 (e.g., inter-State suppliers, casual taxable persons, persons liable under reverse charge, e-commerce operators).
• Applies only to the first return after registration is granted — subsequent returns follow the normal periodic cycle without any interim carry-forward.
• Does not add anything for voluntary registration where no prior liability existed before the effective date, because there is no interim taxable period to sweep in.

Worked Examples

Example 1 — Application within 30 days. A trader in Delhi crosses the ₹40 lakh goods threshold and becomes liable to register on 5 August 2026. She applies for registration on 12 August 2026 and the GSTIN is granted on 20 August 2026. Because the application was within 30 days, registration is effective from 5 August 2026.

All taxable supplies made between 5 August and 19 August must be reported in her first return for August, and tax on them paid accordingly. She may also issue revised tax invoices under Section 31(3)(a) for supplies made in this interim period, so that her customers can claim input tax credit.

Example 2 — Interim sales quantified. Suppose in that 5–19 August window the trader made taxable supplies of ₹6,00,000 at 18% GST. Even though her GSTIN went live only on 20 August, her first GSTR-3B must include output tax of ₹1,08,000 (₹54,000 CGST + ₹54,000 SGST) on that interim turnover, over and above sales made from 20 August onward. If she had failed to sweep in the interim figures, that ₹1,08,000 would have been under-declared and exposed to interest and penalty on later scrutiny.

Step-by-Step in Practice

• Fix the exact date you became liable (threshold crossing or a Section 24 trigger) and keep evidence.
• File the registration application within 30 days so the effective date maps back to the liability date.
• Once the GSTIN is granted, issue revised tax invoices under Section 31(3)(a) for interim-period supplies.
• Compile the interim outward supplies and add them to your first GSTR-1 and GSTR-3B.
• Pay the tax on interim supplies with the first return; reconcile with the revised invoices issued.

Common Mistakes & Practical Notes

• Section 40 governs outward supplies only; input tax credit on inward supplies of the interim period is governed by Section 18(1)(a) and revised invoices, not by Section 40.
• Treating the first return as covering only post-GSTIN sales — the interim window is the whole point and must be included.
• Missing the 30-day application window can make registration effective only from the grant date, potentially leaving earlier supplies unregistered and exposed to penalty.
• Forgetting to issue revised invoices under Section 31(3)(a) within one month of registration, which blocks customers from claiming ITC on interim supplies.
• Poor record-keeping of the liability date, application date and grant date, which are essential to support the first return.

Penalties, Timelines & Related Sections

Section 40 itself does not prescribe a penalty, but failure to declare interim outward supplies means unpaid tax, which attracts interest under Section 50 and potential penalty for short payment. Late filing of the first return still attracts late fee under Section 47. Section 40 works with Sections 22 and 24 (liability to register), Section 25 (procedure and effective date of registration), Section 31(3)(a) (revised invoices for the pre-registration period) and Section 18(1)(a) (ITC on stock held on the day before registration). The first return itself is furnished under Sections 37 and 39 in Forms GSTR-1 and GSTR-3B.

Recent Amendments & Context

The substance of Section 40 has remained stable since GST rollout in 2017; it is a facilitating provision rather than a frequently amended one. The practical context that keeps evolving is the registration timeline under Rule 8/9 (including Aadhaar authentication and, in flagged cases, physical verification), which can lengthen the gap between liability and grant of GSTIN — making a clean Section 40 first return even more important. Taxpayers should always align the interim declaration with the effective date shown on the registration certificate (Form GST REG-06).