Compliance Calendar

September 2026 Tax Audit, Advance Tax and AGM Deadlines

The critical 2026 transition detail: FY 2025–26 tax audits still use Forms 3CA or 3CB with Form 3CD—not the new Form 26. Use this verified deadline and records checklist for September.

NRS Editorial Desk · Published 2026-09-02 · 11 min read

September 2026 is a deadline-heavy month for finance teams. A tax audit for FY 2025–26, the second advance-tax instalment for Tax Year 2026–27, and the ordinary AGM timeline for many companies with a 31 March year-end can overlap. The important point is not to treat these as one generic checklist: they arise under different statutes, apply to different periods and contain different exceptions.

September 2026 compliance calendar at a glance

The 2026 transition trap: Form 26 is not used for AY 2026–27

The Income-tax Act, 2025 took effect from 1 April 2026, but that does not move the FY 2025–26 tax audit into the new form. The official Income Tax Department transition guidance says that the audit for FY 2025–26 / AY 2026–27 remains under the Income-tax Act, 1961 and must use Form 3CA or Form 3CB together with Form 3CD. Its due date is 30 September 2026.

This distinction matters operationally. Selecting the wrong period, assessment year or form can delay assignment and completion. In the same month, however, the advance-tax payment for income earned during Tax Year 2026–27 is governed by the new Income-tax Act, 2025. September therefore requires teams to work with both transition frameworks without mixing them.

Who needs a Section 44AB tax audit for FY 2025–26?

International or specified domestic transaction cases with a report under Section 92E follow a different specified-date route and should not be forced into the standard 30 September matrix. Likewise, a lower-than-presumptive-profit case cannot be decided from turnover alone.

Three Form 3CD reconciliations to finish before the portal step

1. Clause 44: GST-wise expenditure classification

Clause 44 requires an expenditure breakup that distinguishes amounts relating to GST-registered and unregistered entities and the prescribed registered-person categories. The practical task is to reconcile the general ledger, vendor GST status and the classification used in Form 3CD. A mismatch is a reason to investigate the records; it should not be described as proof that an automated scrutiny notice will follow.

2. Clause 22 and Section 43B(h): micro and small enterprise dues

Clause 22 captures the Section 43B(h) position for sums payable to micro or small enterprises beyond the time allowed by Section 15 of the MSMED Act. The review should identify the supplier's qualifying status, acceptance date, agreed credit period, payment date and year-end balance. The consequence is not a permanent loss in every case: subject to the applicable law, a disallowed amount may become deductible in the year of actual payment.

3. Clause 34 and TDS/TCS reporting

Clause 34 requires detailed TDS and TCS reporting. Under Section 40(a)(ia), the 30% disallowance is not a flat adjustment to every expense. It concerns a sum payable to a resident on which tax was deductible but was not deducted, or was deducted and not deposited by the return-filing due date, subject to statutory relief and later-year deduction rules.

Tax audit e-filing: upload alone does not complete the process

The official e-filing process requires the taxpayer to add or assign the Chartered Accountant, the CA to accept the request and submit the report using the prescribed authentication, and the taxpayer to accept and e-verify it from the Worklist. The Income Tax Department's process flow states that submission is completed after the taxpayer's acceptance. Teams should therefore schedule the acceptance step before the deadline instead of waiting for the final portal hour.

Section 271B permits a penalty for failure to get the accounts audited or furnish the report: 0.5% of sales, turnover or gross receipts, or ₹1,50,000, whichever is lower. Section 273B protects a person who proves reasonable cause, so the penalty should not be described as automatic in every delayed case.

Advance tax due on 15 September 2026: use the new Act

The 15 September 2026 instalment relates to income earned during Tax Year 2026–27 and is governed by the Income-tax Act, 2025. Under Section 404, advance tax is generally payable where the amount computed under the advance-tax provisions is ₹10,000 or more. The regular cumulative schedule remains 15% by 15 June, 45% by 15 September, 75% by 15 December and 100% by 15 March.

Taxpayers declaring presumptive income under Section 58(2), Table Sl. No. 1 or 3, follow a different route: the official guidance says 100% is payable in one instalment by 15 March. Resident senior citizens without business or professional income also require the specific advance-tax exemption check. Do not apply the September 45% line mechanically to every individual or presumptive taxpayer.

For Tax Year 2026–27, short-payment interest sits under Sections 424 and 425 of the Income-tax Act, 2025. These correspond to the familiar Sections 234B and 234C of the old Act. The Income Tax Department says the interest policy and rates remain unchanged, but the correct statutory reference depends on the income period.

Section 425: the 45% benchmark, 36% tolerance and 3% interest

For a taxpayer on the regular instalment schedule, Section 425(1) sets 45% of the tax due on returned income as the cumulative benchmark for 15 September and prescribes simple interest of 3% on the shortfall from that benchmark. The Income Tax Department's FAQ explains the same calculation as 1% simple interest for three months. Section 425(2), however, says that no interest under subsection (1) is payable for the September instalment if the advance tax paid by 15 September is at least 36% of the tax due on returned income. The 36% tolerance affects the deferment-interest calculation; it does not replace the statutory 45% instalment benchmark.

Section 425(4) also provides conditional relief where a shortfall results from under-estimating or failing to estimate capital gains, income referred to in Section 2(49)(n), business or professional income accruing or arising for the first time, or qualifying dividend income. The relief applies only when the tax attributable to that income is paid in the remaining advance-tax instalments, if any, or by 31 March of the tax year. It removes the specified Section 425 deferment interest; it does not erase the underlying tax liability or every other possible interest consequence.

Does every company have a 30 September 2026 AGM deadline?

No. For a company with a 31 March 2026 year-end, the ordinary six-month rule points to 30 September 2026. But Section 96 excludes One Person Companies from the AGM requirement, allows nine months from the close of the first financial year for the first AGM, limits the gap between AGMs to 15 months, and permits the Registrar to extend an AGM other than the first by up to three months for a special reason.

A general meeting normally requires 21 clear days' notice under Section 101. An AGM may be called on shorter notice with consent from at least 95% of the members entitled to vote. Because service mode and clear-day computation matter, a universal claim that every notice must be sent on exactly 8 September is unsafe.

• Complete the board and statutory-audit process and confirm that the financial statements and reports are ready for circulation.
• Check the company's articles, member list, notice mode, meeting venue or permitted electronic arrangements and the business actually requiring approval.
• Do not treat auditor reappointment, dividend, director retirement, DIR-8 or MBP-1 as universal AGM actions; include each only where legally and factually applicable.
• File the financial statements in AOC-4 or the applicable variant within 30 days of the AGM under Section 137.
• File the annual return in MGT-7 or MGT-7A, as applicable, within 60 days of the AGM under Section 92.

If the AGM is actually held on 30 September 2026, the 30-day and 60-day periods ordinarily point to 30 October and 29 November 2026. The applicable form, attachments, certification and any event-specific filings still depend on the company category and meeting decisions.

September closing checklist for finance teams

• Confirm whether the FY 2025–26 audit falls under Section 44AB, a presumptive-tax exception or the Section 92E timeline.
• Freeze the trial balance and reconcile turnover across books, GST returns, e-invoices, bank receipts and the cash-percentage tests.
• Prepare supplier-wise MSME status and ageing evidence rather than relying only on a ledger name or Udyam number.
• Reconcile TDS/TCS returns, challans, certificates and expense ledgers for Clause 34 and Section 40(a)(ia).
• Assign the correct audit form and AY to the CA; reserve time for taxpayer acceptance and download the completed acknowledgement.
• Estimate Tax Year 2026–27 income using actual results and credible forecasts, then test the 15 September advance-tax requirement under the new Act.
• For a company, calculate the AGM deadline from its own financial year, incorporation date, previous AGM and any ROC extension—not from a generic calendar alone.
• Create a post-AGM filing list with responsible owners, due dates, board or member approvals and evidence of submission.

Quick answers to September 2026 search questions

Is Form 26 used for the tax audit due on 30 September 2026?

No. For FY 2025–26 / AY 2026–27, use Form 3CA or 3CB with Form 3CD. New Form 26 applies to Tax Year 2026–27 and is due on 30 September 2027.

Is ₹75 lakh the professional tax-audit threshold?

No. The ordinary professional threshold is ₹50 lakh. ₹75 lakh is the enhanced Section 44ADA presumptive-scheme ceiling for an eligible case where cash receipts do not exceed 5%.

Does a Section 44ADA taxpayer pay 45% advance tax by 15 September?

Not under the regular instalment schedule. The new Act places eligible presumptive taxpayers under Section 58 on the single-instalment route: 100% by 15 March, subject to the taxpayer actually qualifying and opting for that scheme.

Are Sections 234B and 234C still the right labels for September 2026 advance tax?

For Tax Year 2026–27, use Sections 424 and 425 of the Income-tax Act, 2025; they correspond to Sections 234B and 234C of the old Act. The old sections remain relevant to defaults arising from FY 2025–26 obligations.

Related NRS deadline and tax-audit guides

When a September compliance review is useful

A focused review is useful when tax-audit applicability is uncertain, the books and GST data do not reconcile, MSME ageing is incomplete, the audit form has not yet been assigned, or the company has not finalised its AGM and post-meeting filings. Businesses working with NRS and Associates from Manjeri, elsewhere in Malappuram district, or Calicut can use the related service and contact routes to share the entity type, financial year, turnover, audit status and exact deadline question.