MAT (Minimum Alternate Tax) vs AMT: Applicability & Computation

Both MAT and AMT exist for the same underlying reason: to make sure a taxpayer with substantial exemptions and deductions still pays some minimum tax, rather than reducing taxable income to near zero through legitimate but aggressive use of the deduction provisions. MAT does this for companies; AMT does the equivalent for non-corporate taxpayers. The mechanics, the base each is computed on, and who actually falls within scope, differ meaningfully between the two.

MAT Under Section 115JB: How It Applies to Companies

Every company is potentially liable for MAT if the income tax payable on its total income, computed under the normal provisions of the Act, works out to less than 15% of its book profit (plus applicable surcharge and health and education cess). Book profit starts from the company's net profit as per its profit and loss account prepared under the Companies Act, then applies a defined list of additions (certain provisions, disallowed expenses, specific reserves) and deletions (specified exempt income, brought-forward business losses or unabsorbed depreciation, whichever is lower) laid down in Section 115JB itself.

This 15% rate has been in place since AY 2020-21; it was reduced from an earlier 18.5% as part of a broader corporate tax relief package. MAT does not apply to companies that have opted for the Section 115BAA (22%) or Section 115BAB (15% for new manufacturing companies) concessional regimes, since those regimes are explicitly carved out of Section 115JB. For a company weighing whether to opt into one of those regimes, MAT exemption is a real part of the calculation, not just the headline rate difference; see our 115BAA vs 115BAB comparison for the full picture.

AMT Under Section 115JC: The Non-Corporate Equivalent

Section 115JC extends a similar minimum-tax concept to non-corporate taxpayers: individuals, HUFs, firms, LLPs, AOPs, BOIs, and certain artificial juridical persons. Unlike MAT, AMT does not apply to every non-corporate taxpayer by default. It is generally triggered only where the taxpayer has claimed specified deductions, such as certain profit-linked deductions under Chapter VI-A or the deduction available to units in a Special Economic Zone, and where adjusted total income exceeds the threshold prescribed in the section. A non-corporate taxpayer who hasn't claimed any of the specified deductions typically stays outside AMT's scope entirely.

Where AMT does apply, it is computed on adjusted total income rather than book profit; this means starting from the taxpayer's regular total income and adding back the specific deductions that made AMT relevant in the first place, then comparing the resulting AMT liability against tax computed under normal provisions and paying whichever is higher.

MAT vs AMT: Side by Side

• Who it applies to: MAT applies broadly to companies; AMT applies narrowly to non-corporate taxpayers claiming specified deductions above a threshold.
• Computation base: MAT uses book profit derived from the profit and loss account; AMT uses adjusted total income derived from regular taxable income.
• Current rate: MAT is 15% of book profit; AMT rates and thresholds are set separately under Section 115JC and should be confirmed for the specific taxpayer category and year.
• Exemptions: companies on the Section 115BAA/115BAB concessional regimes are exempt from MAT; non-corporate taxpayers with no specified deductions claimed generally fall outside AMT without needing a formal exemption.
• Credit mechanism: MAT credit carries forward under Section 115JAA; AMT credit carries forward under Section 115JD, each set off against future years' normal tax once it exceeds MAT/AMT for that year.

MAT and AMT Credit: Getting the Money Back

Neither MAT nor AMT is a permanent extra cost by design; both build in a credit mechanism so the additional tax paid in a low-book-profit or high-deduction year isn't simply lost. The excess of MAT (or AMT) paid over what would have been payable under normal provisions is carried forward as credit, available for set-off in a future year once the taxpayer's normal tax liability exceeds the MAT/AMT figure for that year, subject to the carry-forward period prescribed under the Act. Tracking this credit accurately year over year, and factoring it into cash flow and tax planning rather than treating each year's MAT/AMT payment as a sunk cost, is a routine but easily overlooked part of corporate tax compliance, particularly for companies with volatile book profit due to depreciation timing, provisions, or one-off accounting entries.

For companies weighing whether staying on the regular regime (with MAT exposure) or shifting to a concessional, MAT-exempt regime makes more sense, this needs to be modelled alongside the broader rate comparison covered in our domestic company tax rate guide, since the MAT credit balance already accumulated can itself be a reason to delay switching regimes in a given year.