Why October 2026 GST return is more important for FY 2025-26?

Overview

October 2026 is a crucial month for GST compliance as it marks the final opportunity to make several adjustments relating to FY 2025-26. From reconciling outward supplies and issuing credit notes to verifying Input Tax Credit (ITC), reversing excess claims and correcting invoice classifications, taxpayers must complete key checks before filing their October GST returns. This article explains 7 important GST compliance points, including supplier follow-ups, GSTR-2B reconciliation and GSTR-9 reporting, to help businesses avoid missed ITC claims, reporting errors, interest and penalties.

Arjuna (Fictional Character):  Krishna, every month, taxpayers diligently file their GST returns, but I keep hearing that this October’s 2026 return is especially important. What's the reason behind this?

Krishna (Fictional Character): Arjuna, you’re right! October’s 2026 GST return carries more significance. Several reconciliation tasks and specific compliance need to be completed before filing October’s GST return, since the window for certain adjustments closes on after that month. This October, taxpayers should be particularly careful about reconciling their books with their returns, ensuring compliance with proper discharge of Output tax and ITC claim, reversals and reclaim and meeting various other reporting requirements. Let’s break down each key point so businesses can stay compliant and avoid penalties.

Arjuna (Fictional Character): Krishna, what are the points that taxpayers should keep in mind while filing October 2026 return?

Krishna (Fictional Character): The following things should be kept in mind while filing October 2026 GST return:

1. Reconciliation of Outward Supplies: Taxpayers must ensure that their books match with the outward supplies disclosed in GSTR-1 and GSTR-3B for FY 2025-26. Any discrepancies in it need to be adjusted in October's 2026 GST return by either adding missing invoices or reducing over already reported values, debit notes and credit notes with respect to invoices raised in FY 25-26 but did not reported or incorrectly reported.

2. Issuance of Credit Notes: Credit notes for overcharged tax or for excess taxable value on invoices of FY 2025-26 can only be issued and reported until the October 2026 GSTR-1/3B return.

3. Reconciliation of Books with GSTR-2B for Input tax credit mismatch: Rule 36(4) of the GST Act mandates the businesses to reconcile their ITC claims with GSTR-2B on an invoice-by-invoice basis, ensuring claims aligned with suppliers reported details. This helps them to validate the ITC and reduces mismatches during GST audits. Following this reconciliation, any ITC remaining can be claimed or reversed in the October 2026 return. According to Section 16(4), ITC on invoices or debit notes of FY 2025-26 must be claimed by 30^th November 2025, making the October 2025 return the final chance for adjustments.

For Example, your supplier filed a GSTR-1 return showing ₹2,500 as tax for your invoice so it is reflected in your GSTR-2B also, but you claimed only ₹2,000 in GSTR-3B in FY 2025-26. October 2026 GSTR-3B return is your last chance to claim the balance ITC of ₹500 (if filed before 30^th November 2026).

4. ITC Reversal: Recipients are required to recalculate the reversal of ITC annually as per the CGST rules (on capital goods, inputs & input services) which was used for making taxable supplies and exempt supplies or used for both business and non-business purposes, and any Short/Excess reversal for the period of 2025-26 identified shall be reversed/claimed upto the return filing for the month of October 2026.

5. Follow up with Vendor: If any invoice pertaining to FY 2025–26 has not been reported by the supplier in any return of FY 25-26 and in 26-27 till September 2026 return then request them to upload it in their GSTR-1 and pay the same in GSTR-3B of October 2026 so it will be reflected in our GSTR-2B, as the October 2026 GSTR-3B is the last chance to claim the ITC of 25-26. Therefore, recipients should follow up with their suppliers to ensure the remaining invoices of FY 25-26 are uploaded in the supplier's GSTR-1 for October 2026. Once the supplier files the invoice, the recipient can claim the ITC in their GSTR-3B for October 2026; otherwise, it becomes ineligible to claim.

6. Amendment of Invoice Classification: If you had mistakenly classified a B2B invoice as B2C or vice versa, then the October return is the last chance to make this correction for invoices related to FY 2025-26, as correcting them ensures proper credit flow and reporting accuracy.

7. GSTR-9 of FY 25-26: The Form GSTR-9 for FY 2025–26 has been opened to filed now on GST portal. ITC related to FY 2025–26 that appears in the GSTR-2B of FY 2026–27 will also be included in Table 8A of GSTR-9 for FY 2025–26. Also, any ITC which is reflected in 25-26 GSTR-2B that pertains to 24-25 is excluded from Table 8A. This means only pure ITC of 25-26 will reflect in Table 8A of GSTR-9, which we can download transaction-wise. This data will help to reconcile figures with books. This will help ensure that the ITC figures are properly reconciled between GSTR-2B, GSTR-3B, and Books.

Arjuna (Fictional Character): Krishna, all these points sound critical. What should taxpayers learn from these guidelines?

Krishna (Fictional Character): Arjuna, these provisions emphasize the importance of reviewing and correcting all aspects of GST filings. Although there’s no option as on date to revise returns once filed, the GST law gives taxpayers ample time to make necessary adjustments before the final deadlines. By carefully reconciling their books, verifying their ITC, and correcting any classification or reporting errors in October 2026, businesses can avoid interest, penalties, and added compliance burdens.