With the September 30, 2026 tax audit deadline approaching, businesses and professionals covered by tax audit need to move beyond simply getting the audit report filed. The more important task is ensuring that the numbers appearing across the books of accounts, audited financial statements, tax audit report, GST records, Form 26AS, AIS and Income Tax Return (ITR) are consistent. Even a small mismatch in turnover, profit, depreciation, expenses, TDS or brought-forward losses can create questions later. The Income Tax Department has specifically reminded taxpayers that tax-audit reports in Forms 3CA-3CD/3CB-3CD for AY 2026–27 are due by September 30, 2026.

For taxpayers facing the deadline, the final days should therefore be used for reconciliation rather than rushing through the filing process. A careful review of the audit report, tax computation and ITR can help identify inconsistencies before they become a compliance problem.

September 30 Tax Audit Deadline: Why the Final Reconciliation Matters

A tax audit does not end with the auditor completing the report.

The information contained in the audit report subsequently needs to flow correctly into the taxpayer's ITR. The Income Tax Department's current guidance confirms that the tax-audit report for FY 2025–26 is governed by the applicable provisions for AY 2026–27, with September 30, 2026 being the audit-report due date where the ITR due date is October 31, 2026.

This makes the reconciliation stage particularly important.

A taxpayer may have correct books of accounts and a correctly prepared audit report, but an error while transferring figures into the ITR can still result in a mismatch.

1. Turnover and Profit Figures Do Not Match

One of the first checks should be the comparison of:

• Gross turnover
• Net turnover
• Gross profit
• Net profit
• Total income
• Balance Sheet figures
• Profit and Loss Account figures

These numbers should be reviewed against the audited financial statements and relevant disclosures in the tax audit report.

For example, if the turnover appearing in the audited accounts differs from the turnover reported in the ITR, the difference should not be ignored simply because the variation appears small.

The taxpayer should identify the reason for the difference and correct the appropriate record before filing.

2. GST Turnover and Income-Tax Turnover Mismatch

GST records are another important reconciliation point.

Businesses should compare their relevant GST turnover information with the turnover appearing in:

Books → Financial Statements → Tax Audit Report → ITR

The figures may not always be identical because different accounting or tax adjustments can apply in particular circumstances. However, where there is a difference, the taxpayer should be able to explain it.

Unexplained differences between GST information and income-tax reporting can attract additional scrutiny.

Therefore, GST returns should be reviewed before the final ITR is submitted.

3. Ignoring Disallowable Expenses

Another common issue is failing to consider expenses that require tax adjustment.

Certain expenses may need to be disallowed or added back while calculating taxable income, depending on the applicable provisions and facts of the case.

Examples can include certain:

• TDS-related disallowances
• Cash-payment related disallowances
• Delayed statutory payments
• Certain delayed payments to eligible micro and small enterprises
• Other expenses identified during the tax-audit process

The tax computation should therefore be compared carefully with the observations and disclosures made during the audit.

4. Missing Tax Auditor Adjustments

A taxpayer should not treat the tax audit report as a document that can be filed separately and forgotten.

The auditor may identify adjustments, disclosures or tax-related items that need to be reflected in the computation.

Before filing the ITR, taxpayers should review the relevant portions of the audit report and verify that the corresponding tax treatment has been considered.

This is particularly important where the final taxable income differs from the accounting profit.

5. Incorrect Brought-Forward Losses

Brought-forward business losses and unabsorbed depreciation can have a significant impact on the tax calculation.

Common problems include:

• Incorrect opening balance
• Wrong year of origin
• Incorrect amount carried forward
• Incorrect set-off
• Claiming an amount that has already been utilised
• Omitting eligible amounts

The Income Tax Department has also clarified that eligible unabsorbed losses carried forward from earlier years continue under the transition to the Income Tax Act, 2025, subject to applicable conditions.

Taxpayers should therefore reconcile the current year's computation with earlier ITRs and tax records before claiming brought-forward amounts.

6. Depreciation Errors

Depreciation is another area that deserves attention.

Businesses should verify:

• Opening written-down value
• Additions
• Deletions
• Date of acquisition
• Date assets were put to use
• Applicable depreciation rate
• Depreciation claimed in the books
• Tax depreciation

An incorrect depreciation figure can affect taxable income and the closing value of assets.

7. TDS, TCS and Advance Tax Credit Mismatch

Tax credits should be checked carefully before the ITR is filed.

Taxpayers should compare their records with:

Form 26AS + AIS + Books of Accounts + TDS/TCS records + Advance Tax Payments

The Income Tax Department lists mismatches involving TDS claims and corresponding income or receipts among common causes of defective returns.

For example, claiming TDS credit against income that has not been properly reported can create an inconsistency.

The taxpayer should therefore ensure that the income corresponding to the tax credit has also been correctly accounted for.

8. Incorrect Tax Audit Report Details

Taxpayers should carefully verify the audit-report information entered into the ITR.

This can include details such as:

• Applicable audit form
• Audit report date
• Filing details
• Acknowledgement number
• Relevant audit information

The current AY 2026–27 ITR validation rules also contain checks around audit-report dates and audit-related information.

A simple data-entry mistake can therefore create an avoidable filing issue.

9. Choosing the Wrong ITR Form

The ITR form should correspond to the taxpayer's income profile and applicable reporting requirements.

Businesses and professionals with audited income should ensure that the selected return form correctly accommodates their business or professional income, Balance Sheet, Profit and Loss Account and other applicable disclosures.

The Income Tax Department identifies failure to properly report business or professional income and financial statements as one category of errors that can contribute to defective returns.

10. Ignoring Auditor's Qualifications or Observations

Taxpayers should read the audit report rather than treating it as a formality.

If the auditor has made an observation, qualification, disclaimer or other relevant remark, the taxpayer should understand whether it affects the tax computation or ITR disclosures.

Any material issue identified during the audit should be discussed with the tax professional before the return is filed.

What Taxpayers Should Reconcile Before September 30

A practical final checklist can include:

Should Taxpayers Wait for a Deadline Extension?

Taxpayers should work with the currently notified deadline rather than relying on requests for an extension appearing on social media or elsewhere.

The Moneycontrol report notes that taxpayers should not assume an October 31 extension unless the CBDT formally notifies it.

As of the current Income Tax Department information, September 30, 2026 remains the applicable tax-audit-report deadline for the specified AY 2026–27 cases.

Final Review Before Filing the ITR

The safest approach is to complete a three-way or multi-source reconciliation:

Audited Financial Statements

↓

Tax Audit Report

↓

Tax Computation

↓

ITR

↓

26AS + AIS + GST + Tax Credits

If any figure differs, the taxpayer should determine why before submission.

Where a material change is made to the accounts or tax computation after the audit report has been filed, the taxpayer should discuss with the tax auditor whether the audit report also needs appropriate revision. The final review should ideally be completed jointly by the taxpayer, accountant and tax auditor wherever applicable.

Conclusion

The September 30, 2026 tax audit deadline is not simply a date for uploading the audit report. It is also an important point for taxpayers to verify whether their financial statements, tax audit disclosures and ITR tell the same financial story.

Turnover, profit, GST figures, depreciation, disallowances, brought-forward losses, TDS, TCS, advance tax and audit-report details should all be reviewed carefully.

A few hours spent reconciling these records before filing can help identify errors that may otherwise result in defective-return issues, additional queries or unnecessary compliance work later.

For taxpayers covered by tax audit, the practical message is straightforward: do not wait for the final day to discover a mismatch. Complete the reconciliation, verify the audit details and file using the applicable deadline and requirements.