Business loan tax rules: Section 43B(h) MSME disallowance and interest deductions

This page applies to all business entities—sole proprietorships, partnership firms, LLPs, and private or public companies—subject to tax audit or computing profits and gains from business or profession in India.

It covers deductions for business interest under Section 36(1)(iii), actual-payment rules for bank interest under Section 43B(d)/(e), the MSME payment disallowance under Section 43B(h), the tax treatment of loan waivers under Section 41(1), and corresponding transitions under the Income-tax Act 2025 (effective 1 April 2026). Detailed individual deductions are treated in The Tax Angle.

Business credit and vendor liabilities are governed by core provisions of the Income-tax Act, 1961 and their mapped provisions in the Income-tax Act 2025:

1. Business interest deduction (Section 36(1)(iii)): The amount of interest paid in respect of capital borrowed for the purposes of the business or profession is fully deductible as a revenue expenditure. However, the borrowed funds must be actively utilized in the business; if borrowed capital is diverted as interest-free advances to directors, sister companies, or personal relatives, interest deductions are proportionately disallowed.
2. Bank interest on actual payment basis (Section 43B(d) and (e)): Any interest payable on any loan or advance from a scheduled commercial bank, financial institution, or systemically important NBFC is deductible only in the previous year in which it is actually paid, irrespective of the method of accounting followed. Under Explanation 3C and 3D, converting unpaid interest into a fresh loan or Working Capital Term Loan (WCTL) is not deemed to be actual payment.
3. The Section 43B(h) MSME disallowance rule: Inserted by the Finance Act, 2023:
   • Any sum payable by an assessee to a Micro or Small Enterprise beyond the time limit specified in Section 15 of the MSMED Act, 2006 (within 15 days without contract, or up to 45 days with written contract) is disallowed as a deduction for that financial year.
   • Crucial statutory exception: The general proviso to Section 43B—which allows deductions if payment is made before the due date of filing the income tax return under Section 139(1)—does not apply to clause (h). If an invoice falls due on 15 March and is paid on 10 May, the expense is disallowed in the year of purchase and can only be claimed in the subsequent financial year when payment is made.
   • Scope restriction: Section 43B(h) applies strictly to Micro and Small enterprises; it does not apply to Medium enterprises or to wholesale/retail traders registered under Udyam.
4. Taxability of waived or settled debt (Section 41(1) and Section 28(iv)): In CIT v. Mahindra and Mahindra Ltd., the Supreme Court ruled that where a loan borrowed for acquiring capital assets (such as machinery or building) is waived by a lender in a One-Time Settlement, the waiver of the principal loan amount is a capital receipt and cannot be taxed as business income under Section 28(iv) or Section 41(1). However, waiver of working capital interest or trading credit that was previously claimed as a tax deduction is taxable as deemed profit under Section 41(1).

Consider how Section 43B(h) operates during the financial year closing:

On 1 February, your company purchases raw materials worth ₹20 lakh from a registered Small enterprise supplier under a written contract specifying a 45-day payment period. The statutory deadline under Section 15 of the MSMED Act is 18 March (45 days).

• Scenario A (Compliant payment): You pay the supplier on 25 March. The full ₹20 lakh is allowed as a business expense deduction in your profit and loss account for that financial year.
• Scenario B (Delayed within financial year): You pay on 28 March (10 days late, but before 31 March). The ₹20 lakh deduction is allowed in that financial year because actual payment occurred before the close of the financial year (though you remain legally liable to pay 3x bank rate compound interest to the vendor under Section 16 of the MSMED Act).
• Scenario C (Delayed across year-end): You pay the supplier on 15 April (after 31 March). Even though you paid before filing your tax return in October, Section 43B(h) disallows the ₹20 lakh deduction for that financial year. The ₹20 lakh is added back to your net business profit, increasing your corporate income tax liability for that year. You can claim the ₹20 lakh deduction only in the subsequent financial year when payment was made.

For bank loans, if you accumulated ₹15 lakh in unpaid cash credit interest and negotiated with your bank to convert that ₹15 lakh into a 3-year term loan (WCTL), your chartered accountant cannot claim the ₹15 lakh as an interest expense deduction. Under Explanation 3C to Section 43B, the deduction is allowed only as and when you actually pay the monthly principal instalments of the new term loan in cash.

The primary compliance disaster occurs when businesses fail to categorize their vendor master databases. Companies frequently treat all suppliers identically, delaying payments to Micro and Small vendors until after 31 March under the mistaken belief that paying before the September/October tax return filing deadline protects the deduction. When the statutory tax auditor completes the audit, large expenditure blocks are disallowed under Section 43B(h), creating unexpected cash tax liabilities.

Another frequent error happens during One-Time Settlements (OTS). When a bank issues an OTS sanction letter waiving ₹50 lakh of accumulated interest and ₹1 crore of principal, business owners often treat the entire ₹1.5 crore waiver as tax-free. While the waiver of principal borrowed for capital assets is exempt under the Supreme Court's Mahindra and Mahindra doctrine, the waiver of accumulated working capital interest that was claimed as a tax deduction in earlier years is fully taxable as deemed business income under Section 41(1).

To optimize business tax deductions and avoid statutory disallowances:

1. Maintain an audited Vendor Classification Register. Demand an updated Udyam Registration Certificate from every supplier and classify them into Micro, Small, Medium, or Trader.
2. Ensure all invoices issued by Micro and Small enterprises are flagged in your ERP or accounting software to trigger payment releases within a maximum of 45 days, particularly invoices dated in January, February, and March.
3. If an MSE supplier delivers defective goods, issue a formal written rejection letter via email within 15 days of delivery. Under Section 2(b) of the MSMED Act, a contemporaneous written dispute stops the 45-day statutory countdown until the dispute is resolved.
4. If you have unpaid bank interest at the end of the financial year, pay the interest arrears before the due date of filing your return under Section 139(1) to claim the full tax deduction under the general proviso to Section 43B.
5. In any One-Time Settlement (OTS) with a lender, insist that the settlement agreement explicitly bifurcates the waiver between capital asset principal, working capital principal, and unpaid interest to minimize tax exposure under Section 41(1).

In Mahindra and Mahindra, the Supreme Court established the definitive distinction between capital loan waivers and trading liability remissions, holding that Section 28(iv) applies only to benefits arising from business that are other than in the shape of money, while Section 41(1) applies strictly where an allowance or deduction was actually claimed in respect of a trading loss or expenditure in prior assessment years.

What is Section 43B(h) of the Income-tax Act? Section 43B(h) is a tax rule that disallows business expense deductions for any purchase from a Micro or Small Enterprise if payment is delayed beyond the statutory deadline of the MSMED Act (within 15 days, or up to 45 days under written agreement) [1].

Can I claim the tax deduction if I pay an MSME vendor before filing my ITR in October? No. Unlike other expenses under Section 43B, the extension up to the ITR filing date does not apply to MSME payments under clause (h). If payment was not made within 45 days and falls after 31 March, the deduction is disallowed for that financial year [1].

Does Section 43B(h) apply to payments made to Medium enterprises? No. Section 43B(h) applies strictly to Micro and Small enterprises. Payments made to Medium enterprises (turnover between ₹50 crore and ₹250 crore) are completely exempt from Section 43B(h) disallowance.

Is a loan waiver from a bank taxable as income? Under the Supreme Court's ruling in CIT v. Mahindra and Mahindra, the waiver of loan principal borrowed for capital assets (such as machinery or factory land) is a tax-free capital receipt. However, the waiver of working capital interest that was previously deducted as an expense is taxable under Section 41(1) [2].

Can I deduct unpaid bank interest if the bank converts it into a new term loan? No. Under Explanations 3C and 3D to Section 43B, converting unpaid interest into a fresh loan or Working Capital Term Loan (WCTL) is not considered actual payment. The tax deduction is allowed only when you make actual cash repayments toward the new loan [1].

• Delayed payments and the MSMED Act — statutory payment timelines and Samadhaan claims.
• MSME definition and Udyam registration — Micro vs Small vs Medium criteria.
• Working capital facilities — WCTL restructuring mechanics.
• The tax angle — complete overview of loan-related tax deductions and exemptions.