Section 43B(h) MSME Clock
The Section 43B(h) MSME clock is the payment deadline that decides when a business can claim a tax deduction for buying from a micro or small enterprise. Under Section 43B(h) of the Income Tax Act, the expense is deductible only in the year it is actually paid if payment runs past the MSMED Act time limit. It matters because a late payment pushes the deduction to a later year and raises this year's taxable profit.
What Is the Section 43B(h) MSME Clock?
Section 43B(h) links your income-tax deduction to how quickly you pay your micro and small suppliers. The “clock” is the payment window set by Section 15 of the MSMED Act 2006: 15 days where there is no written agreement, or the agreed date up to a maximum of 45 days where there is one. Pay within the clock and you deduct the expense normally; miss it, and the deduction is deferred to the year you actually pay.
An Indian business meets this rule at year-end, when the auditor reviews outstanding balances owed to suppliers flagged as micro or small on the Udyam portal. Any such balance unpaid beyond the clock as at 31 March is added back to taxable income for that year. Because it is a timing rule, the money is not lost — but the tax on it is pulled forward, which can hurt cash flow in a tight year.
Key terms
- Accounts Receivable Aging Schedule — A bucketed list of unpaid amounts by age — the payables mirror of it drives 43B(h).
- Days Sales Outstanding (DSO) — How long money stays uncollected; the payables side is what 43B(h) polices.
- Dunning Letters — Payment-reminder notices used to keep the clock in check.
Why the Section 43B(h) MSME Clock Matters
Getting the clock wrong has direct tax and cash consequences:
- Deduction deferred, tax pulled forward — An unpaid micro/small balance beyond the window is disallowed this year, so you pay tax on profit you have not really made yet.
- Cash-flow squeeze at year-end — The added-back amount can create an unexpected tax outflow in March when cash is already tight.
- Audit and disclosure exposure — Auditors must report MSME dues and delays; a pattern of late payment is visible in the accounts and to the department.
- Supplier relationships and interest — The MSMED Act also entitles the supplier to interest on delayed payments, adding cost on top of the tax timing hit.
- Only reversed when paid — The deduction returns only in the year of actual payment, so persistent delays keep shifting the benefit further out.
How the Section 43B(h) MSME Clock Works – Step by Step
The clock runs on each purchase from a registered micro or small supplier:
- 1Identify the supplier's status
Confirm from the supplier's Udyam registration whether they are micro or small — the rule does not touch medium enterprises or unregistered suppliers.
- 2Start the clock on acceptance
The window begins on the day goods or services are accepted; the invoice date is the practical trigger recorded in the ledger.
- 3Apply the 15 or 45 day limit
With no written agreement the limit is 15 days; with an agreement it is the agreed date, capped at 45 days.
- 4Check status at 31 March
At year-end the accountant lists micro/small balances still unpaid beyond the window.
- 5Add back the disallowed amount
Unpaid-beyond-limit balances are added to taxable income in the computation; they are deducted again in the year they are paid.
Section 43B(h) MSME Clock: A Practical Example
| Particulars | Amount (INR) | Treatment |
|---|---|---|
| Purchase from a small (Udyam) supplier, 10 Mar 2026 | 5,00,000 | Booked as expense; no written agreement, 15-day clock |
| Due date under Section 15 (10 Mar + 15 days) | 25 Mar 2026 | Payment deadline for a normal deduction |
| Amount unpaid on 31 Mar 2026 | 5,00,000 | Beyond the clock → disallowed under 43B(h) for FY 2025–26 |
| Paid on 20 Apr 2026 | 5,00,000 | Deduction allowed in FY 2026–27 |
A Delhi manufacturer buys ₹5,00,000 of components from a small Udyam-registered supplier on 10 March 2026 with no written agreement, so the 15-day clock ends on 25 March. The bill is still unpaid on 31 March, so the ₹5,00,000 is added back to FY 2025–26 taxable income. When it is paid on 20 April 2026, the deduction is allowed in FY 2026–27 — the benefit is only delayed, not denied.
applied in these ways:
Statutory Position and Due Dates for Section 43B(h)
| Provision | Applies to | Due date / threshold |
|---|---|---|
| Section 43B(h), Income Tax Act 1961 (inserted by Finance Act 2023) | Buyers claiming a deduction for purchases from micro/small enterprises | Effective from AY 2024–25 (FY 2023–24) |
| MSMED Act 2006, Section 15 – no written agreement | Any micro/small supplier | Payment within 15 days of acceptance |
| MSMED Act 2006, Section 15 – written agreement | Any micro/small supplier | Agreed date, capped at 45 days |
| Enterprise coverage | Micro and small only | Medium enterprises are outside 43B(h) |
Law stated as at 22 July 2026. The disallowance is a timing difference: the deduction is allowed in the year the payment is actually made. Verify supplier status from the current Udyam certificate before applying the clock.
Common Mistakes With Section 43B(h)
The clock is often mis-applied in these ways:
- Treating all suppliers as covered — Applying 43B(h) to medium enterprises or unregistered vendors wrongly inflates the add-back → check Udyam status; only micro and small qualify.
- Using 45 days by default — Assuming a 45-day window without a written agreement is wrong — the limit is 15 days absent an agreement → confirm whether a written agreement exists.
- Missing the year-end review — Not scanning payables at 31 March lets disallowed balances slip the computation → run an MSME ageing report before finalising.
- Forgetting the reversal — Failing to claim the deduction in the year of actual payment loses it permanently → track disallowed items and deduct on payment.
The Section 43B(h) MSME clock is the payment deadline that decides when a business can claim a tax deduction for buying from a micro or small enterprise. Under Section 43B(h) of the Income Tax Act, the expense is deductible only in the year it is actually paid if payment runs past the MSMED Act time limit. It matters because a late payment pushes the deduction to a later year and raises this year's taxable profit.
Need help with Section 43B(h) MSME Clock?
Section 43B(h) MSME Clock sits inside your day-to-day books. Patron's CA-led team keeps them accurate, compliant and audit-ready.
Applicable framework: Income Tax Act 1961 (Section 43B(h), Finance Act 2023); MSMED Act 2006 (Section 15). For general information only, not professional advice. Verify the current position for your entity before acting.