A trading company closes the year with a genuine business loss of ₹40 lakh. The books are clean and the loss is properly computed. The return, however, is filed three weeks after the due date because the audit ran late. The next year the business recovers and earns a profit, and the management expects the old loss to absorb it. It cannot. The loss was real, but the right to carry it forward was lost on the day the due date passed. This article explains the timing rule, what else must be right for a loss to survive, and how to protect it.
Business, speculation, specified business and capital losses can be carried forward only if they are determined in a return filed within the due date. This rule is in section 80 of the Income-tax Act, 1961 and section 121 of the Income-tax Act, 2025. A belated return still reports the loss but cannot carry it forward. House property loss and unabsorbed depreciation are treated differently.
The rule: a loss return must be filed within the due date
Under the Income-tax Act, 1961, section 80 provides that losses under the business, speculation, specified business and capital gains provisions can be carried forward only if they are determined in pursuance of a return filed within the time allowed under section 139(3), which in turn refers to the section 139(1) due date.
The Income-tax Act, 2025, in force from 1 April 2026, retains the same principle. Section 121 ("Submission of return for losses") states that a loss covered by sections 111(1), 112(1), 113(2), 114(2) and 115(2) cannot be carried forward and set off unless it has been determined in pursuance of a return filed under section 263(1), the provision that fixes the due date.
The consequence is binary. A belated return is still a valid return for reporting income and the current year's loss, but the loss is not carried forward to future years. There is no partial benefit and no automatic grace period.
The due-date rule is about the year of the loss. If the loss-year return is late, the loss is gone, even if every later return is filed on time.
Which losses are affected and which are not?
| Type of loss | Old section (1961 Act) | Set off in future years against | Carry-forward period | Due-date return needed? |
|---|---|---|---|---|
| Business loss (non-speculative) | 72 | Business income | 8 assessment years | Yes |
| Speculation business loss | 73 | Speculation income only | 4 assessment years | Yes |
| Specified business loss (section 35AD) | 73A | Specified business income only | No time limit | Yes |
| Short-term capital loss | 74 | Short-term or long-term capital gains | 8 assessment years | Yes |
| Long-term capital loss | 74 | Long-term capital gains only | 8 assessment years | Yes |
| House property loss | 71B | House property income only | 8 assessment years | No |
| Unabsorbed depreciation | 32(2) | Any income other than salary | No time limit | No |
Under the Income-tax Act, 2025, the corresponding provisions are section 110 (house property), section 111 (capital gains), section 112 (business), section 113 (speculation) and section 114 (specified business), with unabsorbed depreciation dealt with in section 33. Losses of earlier years are preserved by the transition provisions and keep their original character and time limit; the clock does not restart on 1 April 2026.
House property loss and unabsorbed depreciation are not listed in section 80 or section 121, so they can generally be carried forward even from a belated return. They are, however, still subject to their own conditions, and claiming them in a late return invites questions that a timely return would avoid.
Return due dates that decide whether your loss survives
For the 2026-27 tax year, the first year under the new Act, section 263 sets the following due dates:
- 31 July 2027 for individuals and others with no business income and no audit requirement.
- 31 August 2027 for taxpayers with business or professional income whose accounts are not required to be audited (a separate tier introduced by the Finance Act, 2026).
- 31 October 2027 for companies and for other taxpayers whose accounts must be audited, and for working partners of such firms.
- 30 November 2027 for taxpayers required to file a transfer pricing report.
For the financial year 2025-26 (assessment year 2026-27), still governed by the 1961 Act, the CBDT extended the return due date for audit cases (other than transfer pricing cases) to 21 November 2026, with the tax audit report due by 21 October 2026. Transfer pricing cases remain due on 30 November 2026. A return filed within an extended due date notified by the CBDT is treated as filed within time.
Do not confuse the belated return window with the due date. A belated return can be filed up to several months later, but for loss carry-forward purposes it is too late.
Timely filing is not enough: other ways losses are lost
Filing on time preserves the right to carry forward. Whether the loss actually survives assessment depends on several other things.
Losses also interact with tax disallowances. If an expense is disallowed in assessment, for example for non-deduction of TDS, the assessed loss shrinks. Our article on TDS disallowance under section 40(a)(ia) explains how that happens.
What a lost loss really costs
A domestic company paying tax under the concessional regime of section 115BAA of the 1961 Act (effective rate 25.168% including surcharge and cess) incurs a business loss of ₹40 lakh. Next year it earns a profit of ₹50 lakh.
Return filed on time: the ₹40 lakh loss is set off, taxable profit is ₹10 lakh and tax is about ₹2.52 lakh.
Return filed late: the loss cannot be carried forward, taxable profit is ₹50 lakh and tax is about ₹12.58 lakh.
The late filing costs roughly ₹10.07 lakh in additional tax, before considering the late fee and interest.
The cost is not only tax. Deferred tax assets recognised in the books may need to be written off, cash flow forecasts that relied on the shield are disrupted, and lenders or investors may ask why a valuable tax attribute was lost through a filing delay. In due diligence, buyers routinely test whether reported tax losses are actually available, which is one reason clean filing history matters. See our guide on financial due diligence scope and deal price.
Missed the due date? Options that remain
Once the due date has passed, the options are limited and none is guaranteed.
- Condonation of delay: the tax administration has power to condone delay in filing a return claiming carry-forward of loss in cases of genuine hardship. An application must explain the reasons for delay with evidence. Relief is discretionary, subject to monetary and time limits set by the CBDT, and can take months.
- Belated return: still file it. It regularises compliance, reports the current year's result and keeps house property loss and unabsorbed depreciation alive.
- Updated return: an updated return cannot be used to declare or increase a loss, so it does not cure a late loss return.
The practical lesson is that the only reliable protection is to file the loss-year return by the due date, even if some figures need to be refined later through a revised return.
Checklist to protect a tax loss
- Diarise the correct due date. Identify which tier applies (non-audit, non-audit business, audit or transfer pricing) and track any CBDT extension.
- Finish the audit early. In audit cases the return cannot be filed before the audit report, so schedule the audit with buffer.
- File on time even if imperfect. A timely original return can be revised; a late return cannot restore the loss.
- Complete the loss schedules. Check current-year set-off, brought-forward set-off and carry-forward schedules against the previous year's return and assessment.
- Track each loss by year of origin. Maintain a loss register showing head, year, amount assessed and expiry.
- Keep evidence ready. Retain invoices, ledgers, stock records and valuation workings that support the loss.
- Review shareholding changes. For closely held companies, test any change in ownership against the continuity condition before the transaction.
Frequently asked questions
Can I carry forward a business loss if I file a belated return?
No. Business, speculation, specified business and capital losses can be carried forward only if the loss-year return is filed within the due date. A belated return reports the loss but does not allow it to be carried forward.
Can house property loss be carried forward from a late return?
Generally yes. House property loss and unabsorbed depreciation are not covered by the due-date condition in section 80 of the 1961 Act or section 121 of the Income-tax Act, 2025, so they can be carried forward even from a belated return, subject to their own limits.
What is the new section for loss returns under the Income-tax Act, 2025?
Section 121 of the Income-tax Act, 2025, titled Submission of return for losses, corresponds to section 80 of the 1961 Act. It requires the loss to be determined in a return filed under section 263(1).
Does a CBDT extension of the due date protect my loss?
A return filed within a due date that the CBDT has formally extended is treated as filed within time. For assessment year 2026-27, audit cases (other than transfer pricing cases) have an extended due date of 21 November 2026.
Can I use an updated return to claim a loss I missed?
No. An updated return cannot be filed to declare a loss or increase a loss already returned. It is meant only for offering additional income.
How long can a capital loss be carried forward?
Capital losses can be carried forward for eight assessment years following the year of loss. Short-term capital loss can be set off against short-term or long-term gains, but long-term capital loss only against long-term gains.
Conclusion
A tax loss is valuable only if the law allows it to be used. That depends on three things: the return for the loss year must be filed by the due date, the loss must be correctly disclosed in the right schedules, and the computation must stand up in assessment. Of these, the due date is the easiest to control and the most expensive to miss.
If your business is heading into a loss year, or you are unsure whether past losses are still available, a review of filing history, loss schedules and assessment records before the next return can protect a benefit that may be worth a significant amount of future tax.
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Talk to usThis article is for general information only and does not constitute professional advice or solicitation. Examples are illustrative and use simplified tax computations. Section references are to the Income-tax Act, 1961 unless stated; from the 2026-27 tax year, the Income-tax Act, 2025 applies. Provisions are summarised as of October 2026. Please refer to the relevant provisions and seek advice on your specific facts.