The 45-Day MSME Payment Rule (Section 43B(h)): A Complete Guide

The 45-Day MSME Payment Rule (Section 43B(h)): A Complete Guide#

One of the biggest systemic issues in the Indian economy is the delayed payment cycle facing Micro and Small Enterprises (MSEs). Large corporations often stretch their payables to 90 or 120 days, starving small vendors of working capital.

To ruthlessly enforce timely payments, the government weaponized the Income Tax Act by introducing clause (h) in Section 43B. This single clause has fundamentally altered how businesses manage their accounts payable.

The Rule: Pay on Time, or Pay Tax#

Section 43B dictates that certain expenses can only be claimed as a deduction in your income tax return in the year they are actually paid, not just when they are accrued in the books.

The Clause (h) Addition: Any sum payable by an assessee (the buyer) to a Micro or Small Enterprise for goods or services must be paid within the time limit specified by the MSMED Act, 2006.

The Time Limits (As per MSMED Act):#

1. If there is a written agreement: Payment must be made within the agreed timeline, but this agreed timeline cannot exceed 45 days.
2. If there is no written agreement: Payment must be made within 15 days from the date of acceptance of the goods or services.

The Disallowance Trap#

What happens if you fail to pay the Micro/Small vendor within 45 days?

• Total Disallowance: The entire expense will be disallowed while calculating your taxable business profit for that financial year.
• Added to Income: The unpaid invoice amount is effectively added back to your net profit, forcing you to pay an immediate income tax (often 30%) on money you haven't even paid to the vendor yet!
• Claimed Later: You can only claim the deduction for that expense in the subsequent financial year in which you actually make the payment to the MSME.

Who is Covered?#

This rule specifically protects Micro and Small Enterprises. Following MSME Ministry Notification S.O. 1364(E) dated 21 March 2025, effective 1 April 2025, the classification thresholds are:

• Micro Enterprise: Investment in Plant & Machinery/Equipment up to ₹2.5 Crore AND Turnover up to ₹10 Crore.
• Small Enterprise: Investment up to ₹25 Crore AND Turnover up to ₹100 Crore.

The test is composite — an enterprise must satisfy both limits; breaching either pushes it into the next higher category (and, once it becomes Medium, outside the protection of Section 43B(h)).

(Note: Medium enterprises and traders are currently excluded from the strict protection of Section 43B(h), though this is a subject of ongoing litigation and clarification).

Action Plan for Businesses#

1. Vendor KYC: Immediately collect the Udyam Registration Certificates from all your vendors. You cannot comply if you don't know who is an MSE and who is not.
2. ERP Updates: Configure your accounting software (Tally, SAP) to red-flag any payable to a verified MSME that is approaching the 40-day mark.
3. Year-End Audit: Before closing your books on March 31st, ensure all MSME invoices older than 45 days are cleared. Any outstanding MSME payable that crosses the March 31st boundary and the 45-day limit simultaneously will trigger immediate tax disallowance.

Worked Example: Computing the Disallowance#

Numbers make this rule concrete. Consider a company that buys raw material from a Udyam-registered Small Enterprise, with no written agreement governing the payment terms (so the statutory limit is 15 days from acceptance, not 45).

• Invoice date: 20 January
• Date of acceptance of goods: 22 January
• Due date under MSMED Act (15 days, no written agreement): 6 February
• Invoice amount: ₹18,00,000
• Amount actually paid by 31 March: ₹6,00,000
• Amount still outstanding on 31 March: ₹12,00,000

Because the buyer paid ₹6,00,000 after the 6 February due date but the balance ₹12,00,000 remains unpaid at year-end, the deduction available on the unpaid portion is blocked for the year. Assuming the company's other computations put it in the highest slab, the tax impact looks like this:

The treatment of the ₹6,00,000 paid before 31 March — late, but within the same financial year — is a point on which the profession is genuinely divided, and it is worth understanding both readings before taking a position.

• The year-end balance view: Section 43B operates by disallowing sums that remain unpaid as on the last day of the previous year. On this reading, an amount cleared before 31 March — even if it missed the MSMED due date — does not form part of the year-end unpaid balance, so no disallowance arises for it.
• The strict-timeline view: Clause (h) is deliberately excluded from the benefit of the proviso to Section 43B that ordinarily allows a deduction where payment is made before the due date for filing the return. On this reading, the statutory 15/45-day limit is the operative test, and a payment that breaches it is deductible only in the year of actual payment.

The two views can produce materially different computations for the same set of facts, and the position taken should be documented and applied consistently rather than decided invoice by invoice. Given the amounts typically involved, this is one to settle with your tax advisor in advance of year-end — not while the return is being filed.

Interaction with Tax Audit Reporting#

For assessees subject to a tax audit, the disallowance under Section 43B(h) does not rely on the assessee self-reporting it correctly — the tax auditor is required to separately report sums payable to Micro and Small Enterprises that remained unpaid beyond the time limit prescribed under the MSMED Act, along with the amount so payable, as part of the particulars furnished in the audit report. This means:

• The auditor will independently verify Udyam registration status of vendors, invoice dates, dates of acceptance, and payment dates — you cannot manage this after the fact by simply omitting the disallowance from your computation of income.
• Any mismatch between what the auditor reports and what is disallowed in the return is one of the most common triggers for automated scrutiny, since the return's computation and the audit report are cross-matched.
• Practically, this means the MSME ageing exercise has to be done before the auditor signs off, not during return filing. Waiting until the return is being prepared is usually too late to gather Udyam certificates or resolve disputed invoices.

Practical Edge Cases#

Part-payments. Only the portion of the invoice still outstanding on 31 March is disallowed — not the full original invoice value. If ₹18,00,000 was billed and ₹6,00,000 paid before year-end, the disallowance computation runs on the ₹12,00,000 balance, as shown in the worked example above.

Disputed invoices. A genuine, documented dispute over quantity, quality, or rate delays the date of "acceptance" (or triggers a fresh "deemed acceptance" clock under the MSMED Act once objections are resolved), which can push out the due date. This is not a loophole to be used loosely — the dispute needs to be raised in writing, ideally within a reasonable period of receiving the goods or services, and properly documented (emails, debit notes, correspondence) so it can be defended on scrutiny. An undocumented, after-the-fact claim of "we disputed it" rarely survives assessment.

Vendors who register under Udyam mid-year. The protection applies from the date the vendor holds a valid Udyam Registration as a Micro or Small Enterprise. Invoices raised and accepted before that registration date generally fall outside the clause's ambit for that period. Track the registration date carefully rather than assuming it applies retrospectively to the whole year.

Vendors who do not disclose MSE status. The buyer's obligation is practically tied to what it knows or ought reasonably to know. If a vendor never furnishes Udyam details despite being asked, the buyer has a reasonable basis for not applying 43B(h) to that vendor — but this needs a paper trail (a vendor onboarding form asking for Udyam status, follow-up requests) rather than an after-the-fact assumption. This is exactly why the "Vendor KYC" step in the action plan above matters — the compliance burden effectively sits with the buyer.

Written Agreement vs No Written Agreement#

Micro/Small vs Medium Enterprises#