Alternate minimum tax is the provision most non-corporate taxpayers have never heard of until it applies to them. It catches LLPs, firms and individuals who claim certain deductions — and it is triggered by the deductions themselves, not by profitability.
Form 29C is the accountant’s report that certifies the computation.
At a glance
- What it is
- Accountant’s report certifying adjusted total income for AMT
- Provision
- Section 115JC(3), read with Rule 40BA
- Who files
- Non-corporate taxpayers claiming specified deductions
- Who signs
- A Chartered Accountant in practice
- Individual threshold
- AMT does not apply where adjusted total income is ₹20 lakh or less
- Credit
- AMT credit under section 115JD
- Under the 2025 Act
- Section 206
How AMT works
AMT is the non-corporate mirror of MAT. The taxpayer computes tax normally, then computes it on adjusted total income at the AMT rate, and pays the higher.
Adjusted total income is total income plus the deductions that caused the problem in the first place — broadly, deductions under Chapter VI-A Part C (the 80-IA to 80-RRB family), the deduction under section 10AA for SEZ units, and the investment-linked deduction under section 35AD, reduced by depreciation that would otherwise have been allowed.
AMT is deduction-driven, not profit-driven. A firm with modest income that claims a large profit-linked deduction can fall into AMT, while a firm with much higher income and no such deduction does not. If you are claiming 80-IAC, 80-IA, 80-IB, 10AA or 35AD, check AMT before you finalise the return.
Who it applies to
| Taxpayer | AMT position |
|---|---|
| LLP or partnership firm claiming the specified deductions | Applies, with no exemption threshold |
| Individual, HUF, AOP or BOI | Applies only where adjusted total income exceeds ₹20 lakh |
| Taxpayer claiming none of the specified deductions | Does not apply |
| Company | Outside AMT — MAT applies instead |
| Taxpayer who opted into the concessional regime under section 115BAC or 115BAD | Generally outside AMT, subject to conditions |
The ₹20 lakh threshold does not save an LLP. It protects individuals, HUFs, AOPs and BOIs only. A firm or LLP is within AMT at any level of adjusted total income once it claims a specified deduction — which is why LLPs claiming profit-linked deductions are the most common AMT cases in practice.
AMT credit
The excess of AMT over normal tax becomes AMT credit under section 115JD, carried forward and set off in later years when normal tax exceeds AMT. As with MAT, the effect is timing rather than absolute cost — provided the taxpayer eventually has years in which normal tax is higher.
That proviso matters. A business whose profile does not change may carry AMT credit for a long time without using it, so the planning question is whether the deduction is worth accelerating the tax.
What Form 29C reports
- Total income as computed under the ordinary provisions
- Deductions claimed under Chapter VI-A Part C, item by item
- Deduction claimed under section 10AA
- Deduction claimed under section 35AD, less depreciation that would have been allowed
- The resulting adjusted total income
- AMT at the applicable rate
- Comparison with normal tax, and the credit arising
It is a short form. Its value is that it forces the comparison to be made and documented, which is precisely the step taxpayers skip.
Deadline
Form 29C is furnished one month before the due date for the return. Where the taxpayer is also subject to tax audit, it sits alongside the audit report in the same filing cycle.
UDIN on Form 29C
Form 29C is a report signed by a practising Chartered Accountant supporting a computation, so the Certificates category applies — UDIN mandatory since 1 February 2019.
Sixty calendar days from upload. Where the form is uploaded without a UDIN and the number is not updated within that window, the CBDT treats it as invalid with all due consequences of law, even after acceptance. Because section 115JC(3) makes the report a requirement, an invalid form leaves the AMT computation unsupported. Revocation closes at 48 hours.
See our guide to UDIN generation.
AMT under the Income-tax Act, 2025
| Subject | 1961 Act | 2025 Act |
|---|---|---|
| Minimum alternate tax and alternate minimum tax | Sections 115JAA, 115JB, 115JC | Section 206 |
| Deductions in respect of certain incomes | Sections 80-IA to 80-RRB | Sections 138 to 152 |
| SEZ units | Section 10AA | Section 144 |
The 2025 Act brings MAT, AMT and the credit provisions together into section 206. Note that the deductions which trigger AMT have themselves been renumbered — the 80-IA to 80-RRB family now sits at sections 138 to 152 — so the cross-references in any AMT working need updating.
Frequently asked questions
Who has to file Form 29C?
A non-corporate taxpayer to whom section 115JC applies, certifying that adjusted total income and AMT have been computed in accordance with the section.
What triggers AMT?
Claiming deductions under Chapter VI-A Part C, section 10AA or section 35AD. Without those, AMT does not arise.
Is there an exemption limit?
Yes, for individuals, HUFs, AOPs and BOIs — AMT does not apply where adjusted total income is ₹20 lakh or less. Firms and LLPs get no such threshold.
Does AMT apply to companies?
No. Companies are subject to MAT under section 115JB and file Form 29B.
What is adjusted total income?
Total income increased by the specified deductions — Chapter VI-A Part C, section 10AA, and section 35AD less notional depreciation.
Is the extra tax lost?
No. It becomes AMT credit under section 115JD, available for set-off in later years when normal tax exceeds AMT.
When is Form 29C due?
One month before the due date for furnishing the return of income.
Which rule prescribes it?
Rule 40BA of the Income-tax Rules, 1962.
Is UDIN required?
Yes, in the Certificates category, with the 60-calendar-day update rule after upload.
Which section replaces 115JC under the new Act?
Section 206, covering MAT, AMT and the related credit.
Does a startup claiming 80-IAC need to think about AMT?
Yes, if it is an LLP. An LLP claiming the 80-IAC deduction has no ₹20 lakh threshold, so AMT should be modelled before the three deduction years are chosen.
In short
AMT is the provision that quietly reduces the value of profit-linked deductions for firms and LLPs. Because it is triggered by claiming the deduction rather than by earning a lot, it should be modelled at the point the deduction is planned — particularly for an LLP, which gets no threshold at all. Form 29C then just documents a comparison that should already have been made.
Micro Advisor advises firms, LLPs and professionals on AMT exposure, credit planning and the related reporting.
References
Disclaimer. General information, not professional advice. AMT rates, thresholds and the interaction with concessional regimes have changed over time; verify the position for the taxpayer and year concerned.