IFF Cut-Off on the 13th: How QRMP Filers Keep Their Buyers Input Credit Flowing

It is Saturday, 29 August 2026, and for every business enrolled in the Quarterly Return, Monthly Payment (QRMP) scheme — that is, registered taxpayers with aggregate annual turnover of up to Rs 5 crore — the compliance clock resets tomorrow, Sunday 30 August 2026, as August closes and the second month of the July-September 2026 quarter ends. The single date that now matters most is 13 September 2026: the cut-off to file the Invoice Furnishing Facility (IFF) for August's outward business-to-business supplies. Miss it, and your buyers wait.

The IFF is, on paper, optional. The GST Network's own IFF FAQ describes it as "a facility provided to quarterly taxpayers who are in QRMP scheme, to file their details of outward supplies in first two months of the quarter." But the consequence of skipping it is anything but optional for the people you sell to. Until a QRMP supplier furnishes an August invoice, that invoice does not appear in the recipient's auto-drafted GSTR-2B, and the recipient cannot claim input tax credit (ITC) on it for August. Tomorrow's watchlist, therefore, is really your buyers' watchlist.

This report sets out the statutory deadlines converging on the fortnight ahead, the system-level events QRMP filers should track, how the compliance cycle intersects with corporate reporting, and a worked example of exactly what a missed 13 September filing costs a buyer in rupees.

Statutory Deadlines

The IFF window for August 2026 (month two, or "M2", of the July-September quarter) opened on 1 September and closes on 13 September 2026. Note that 13 September 2026 falls on a Sunday — and GST statutory due dates are not automatically extended for weekends unless the Central Board of Indirect Taxes and Customs (CBIC) issues a specific notification, so filers should treat Friday 11 September as their practical working deadline rather than banking on a Monday grace day.

The IFF carries a per-month ceiling: as the GST portal confirms, records with a cumulative value exceeding Rs 50 lakh cannot be filed in a single IFF period, and any excess must be deferred to the next reporting window. Invoices not furnished via IFF for July and August will instead be reported in the quarterly Form GSTR-1 for July-September 2026, due by 13 October 2026 — a delay of up to a month in credit reaching the buyer. The underlying obligation to furnish outward-supply details flows from Section 37 of the Central Goods and Services Tax Act, 2017, the text of which is hosted on the official India Code repository.

Here is the compliance calendar for the fortnight ahead, anchored to the July-September 2026 quarter:

The 15 September 2026 advance-tax instalment is the other unmissable date in this window. Under Section 211 of the Income-tax Act, 1961, a taxpayer must have paid at least 45% of the estimated annual tax liability, cumulatively, by 15 September — following the 15% due by 15 June, and ahead of 75% by 15 December and 100% by 15 March. The Income Tax Department sets out these instalment percentages on its official portal at incometax.gov.in. A shortfall attracts interest under Section 234C, so QRMP business owners juggling the 13 September IFF should not let the 15 September advance-tax cheque slip in the same week. Our advance tax glossary entry explains how the instalment schedule works.

Market Events

The dominant "market event" for QRMP filers this fortnight is not a central-bank meeting but the mechanical behaviour of the GST portal itself. Once the IFF window shuts at the end of 13 September 2026, the facility flips to view-and-download only: the portal FAQ states that after the deadline a taxpayer "can view/download only" and "cannot save or submit new details." There is no self-service extension. That single system rule is why the 13th behaves like a market close — orders left unplaced simply do not execute.

A second, quieter event is the auto-population of GSTR-2B. For a buyer, the statement generated from a supplier's timely IFF filing is the document that unlocks ITC. If a QRMP supplier furnishes August invoices by 13 September 2026, those records flow into the recipient's GSTR-2B for the August period; if the supplier waits for the quarterly GSTR-1 on 13 October 2026, the credit lands roughly 30 days later. For a buyer running on thin working capital, that month of blocked credit is a real financing cost.

The macro backdrop frames all of this. The Reserve Bank of India's Monetary Policy Committee cut the repo rate to 5.25% in December 2025, as we reported in our coverage of the surprise December easing. With the marginal cost of short-term borrowing anchored around that policy rate, every month of ITC that a buyer cannot claim is, in effect, working capital financed at prevailing bank rates — a concrete reason for suppliers to treat the 13 September IFF as a customer-service obligation, not a paperwork chore. Investors modelling the drag on their own capital can sketch the compounding cost using the SIP calculator.

Earnings

No specific listed-company results are confirmed on the newsroom calendar for tomorrow, 30 August 2026, so this section flags the compliance angle rather than an earnings schedule — in keeping with a zero-invention policy on results dates. The point worth watching is structural: the same 13 September 2026 IFF discipline that governs a small QRMP vendor also shapes the reported numbers of the large companies that buy from it.

Listed enterprises reconcile purchase registers against auto-drafted GSTR-2B before finalising indirect-tax positions. When a QRMP supplier misses the 13 September IFF, the buyer's provisional ITC for August is not available, and reconciliation teams must decide whether to defer the credit to the July-September quarter closing on 13 October 2026. Multiply that across hundreds of small vendors and the timing of IFF filings becomes a genuine, if unglamorous, input into working-capital and tax-line disclosures. Analysts scrutinising quarterly results due later in the reporting season would do well to remember that the Rs 50 lakh monthly IFF ceiling and the 13th-of-the-month cut-off sit upstream of every ITC figure.

The reverse lesson holds for QRMP sellers who supply listed corporates: a large customer's accounts-payable team may treat a missed IFF as a reason to hold payment until the credit is visible. Furnishing B2B invoices by 13 September 2026 is, quite literally, a way to get paid on time.

What a Missed IFF Really Costs Your Buyer

To make the stakes concrete, consider a QRMP supplier who raises three B2B invoices in August 2026 and is deciding whether to file the IFF by 13 September or let the invoices roll into the quarterly GSTR-1 on 13 October. The GST here is standard 18%, and the "credit delayed" column is the ITC the buyer cannot claim for August if the supplier skips the IFF:

On the Rs 40 lakh invoice, the buyer's Rs 7,20,000 of input credit is deferred by roughly 30 days — from the August GSTR-2B to the quarter-end GSTR-1 filed by 13 October 2026 — purely because the supplier did not spend a few minutes on the portal by the 13th. Note too that the Rs 40 lakh figure sits within the Rs 50 lakh single-period IFF ceiling, so it can be furnished in one August IFF; a Rs 60 lakh month would need part of the value carried forward. Suppliers choosing the QRMP scheme's tax-payment mechanics can pay August tax through Form PMT-06 by 25 September 2026 using either the Fixed Sum Method or the self-assessment method. For the full mechanics of the scheme, see our explainer on how QRMP splits quarterly returns from monthly payments.

FAQ

What is the IFF due date for August 2026?

The IFF for August 2026 — the second month of the July-September quarter — must be filed by 13 September 2026. Because that date is a Sunday and GST due dates are not auto-extended for weekends without a CBIC notification, treat 11 September 2026 as your working deadline.

Is filing the IFF mandatory?

No. The GST portal's IFF FAQ describes it as "an optional facility provided to quarterly taxpayers only." However, if you have already saved invoices with the IFF in "Submitted" status, filing it by the 13th becomes mandatory, and skipping it blocks your buyers' input tax credit for that month.

What happens if a QRMP supplier misses the 13 September IFF?

The August invoices will instead be reported in the quarterly Form GSTR-1 for July-September 2026, due by 13 October 2026. The buyer's input tax credit for those invoices is consequently delayed by up to 30 days, appearing in the quarter-end GSTR-2B rather than the August statement.

Is there a value limit on the IFF?

Yes. Records with a cumulative value exceeding Rs 50 lakh cannot be furnished in a single IFF period, as confirmed on the GST portal. Any excess must be deferred to the next reporting window or the quarterly GSTR-1.

Who can use the QRMP scheme and the IFF?

Registered taxpayers with aggregate annual turnover of up to Rs 5 crore who have opted into QRMP and filed their latest applicable return. The IFF is available only for the first two months (M1 and M2) of each quarter; the third month's supplies are captured in the quarterly GSTR-1.

When is the next advance-tax instalment due?

The second instalment is due on 15 September 2026, by which date at least 45% of the estimated annual tax liability must be paid cumulatively under Section 211 of the Income-tax Act, 1961. A shortfall attracts interest under Section 234C.

How do QRMP filers pay August tax if returns are quarterly?

Through Form PMT-06, due by 25 September 2026 for August, using either the Fixed Sum Method (a system-computed challan) or the self-assessment method based on actual liability. The return itself, Form GSTR-3B for the quarter, is filed after the quarter ends.