MSME 45-Day Payment Rule: How Section 43B(h) Bites Buyers

If you run a business and buy from small vendors, one quiet line in the Income Tax Act can suddenly inflate your tax bill: Section 43B(h). Inserted by the Finance Act 2023 and live from assessment year 2024-25, it ties your right to claim an expense to whether you paid your micro and small suppliers on time. Pay late, and the taxman can disallow the deduction in that very year. This is the MSME 45-day payment rule, and most owners only discover it when their accountant flags it at year-end.

What Section 43B(h) actually says

The provision is short but sharp. Any sum payable to a micro or small enterprise beyond the time limit fixed in Section 15 of the MSMED Act, 2006 can be deducted only in the year you actually pay it — not in the year you booked the purchase. Section 43B normally covers things like taxes, PF and bank interest, which are allowed only on payment. Clause (h) extends that same logic to your small vendors' bills.

The catch is timing. For most items under Section 43B, you get a grace period until the ITR filing due date. Clause (h) deliberately removes that cushion. If the payment crosses the MSMED deadline and is still unpaid on 31 March, the expense is knocked out of that financial year's profit-and-loss for tax purposes.

The 45-day and 15-day clock, explained

The deadline is not a flat 45 days for everyone. Section 15 of the MSMED Act sets two scenarios:

• With a written agreement: you must pay within the period agreed in the contract, but that period can never exceed 45 days from the day you accept the goods or services.
• Without any agreement: the limit drops to just 15 days from the date of acceptance or deemed acceptance.

So a vague "net 60" or "net 90" credit term on a small supplier's invoice is legally meaningless — the law caps the enforceable window at 45 days. The clock starts from acceptance, not from the invoice date, which matters if you inspect goods before accepting them.

Who counts as a 'micro or small' supplier

This is where many buyers trip up. The rule bites only if your supplier is a registered micro or small enterprise that has a valid Udyam registration. Three filters decide whether 43B(h) applies to a given vendor:

1. Size: the enterprise must be micro (plant and machinery up to ₹2.5 crore, turnover up to ₹10 crore) or small (up to ₹25 crore and ₹100 crore respectively, under the revised 2025 limits). Medium enterprises are excluded.
2. Registration: the supplier should hold Udyam registration at the time of the transaction. If they registered later, the earlier dues may not be caught.
3. Activity: crucially, traders are not covered as suppliers. A government clarification kept wholesale and retail traders outside Section 15 for this purpose, even though they can register on Udyam for priority-sector lending. Only manufacturers and service providers trigger 43B(h).

The practical takeaway: ask vendors for their Udyam number and whether they are classified micro, small or medium, and keep it on file.

What the disallowance really costs you

The good news is that 43B(h) does not destroy a deduction — it defers it. Say you owe a small manufacturer ₹10 lakh in March, miss the 45-day window, and clear it in May. That ₹10 lakh is added back to your profit for the year that just ended, so you pay tax on it now. You then claim it in the next year when payment goes out.

The damage is a cash-flow and timing hit, not a permanent loss. But for a profitable firm, an unexpected addition of several lakhs to taxable income can mean a sizeable advance-tax shortfall, interest under Sections 234B and 234C, and a nasty surprise at filing. For a business sitting on thin margins, it can flip a planned refund into a payable.

There is a second sting. The MSMED Act also imposes compound interest on delayed payments — at three times the RBI-notified bank rate — and that penal interest is itself not deductible. So a late payment can hurt twice over.

Why this rule was created

The intent is genuinely pro-small-business. Indian MSMEs have long complained that large buyers stretch payments for months, choking the working capital of the very firms that employ the most people. Earlier remedies — going to the MSME Samadhaan portal or the Facilitation Council — were slow and adversarial; few small vendors wanted to sue a big customer they depend on.

Section 43B(h) flips the incentive. Instead of making the supplier chase the buyer, it makes the buyer's own tax outgo depend on prompt payment. The threat of a disallowed deduction is a far stronger nudge than a complaint nobody files. In its first full year, anecdotal reports suggested many corporates began clearing small-vendor dues before 31 March specifically to dodge the add-back.

A practical checklist for buyers

If you are on the paying side, a little process saves a lot of tax pain:

• Tag your vendors. Build a master list flagging which suppliers are Udyam-registered micro or small enterprises versus medium or trader.
• Collect Udyam certificates and refresh them yearly, since classification can change as a firm grows.
• Fix payment terms in writing at 45 days or less for covered vendors, and set system alerts at, say, day 40.
• Prioritise small-vendor payables in March. Clear anything within the window before the year closes to avoid the harsher 31 March test.
• Reconcile at year-end. Have your accountant identify any covered dues outstanding beyond the limit so you can either pay or correctly add them back.

What suppliers should know — and what comes next

If you are a micro or small supplier, the rule is a quiet weapon in your favour: simply being Udyam-registered and mentioning it on invoices makes your buyers far keener to pay you inside 45 days. Always state your registration status and the statutory due date on every bill.

The one open frustration is that the law currently shields only manufacturers and service providers, leaving traders without the same protection — an anomaly that small-trade bodies have asked the government to fix. There have also been calls to relax the strict 31 March trigger and align it with the filing-due-date grace given to other 43B items.

For now, the rule stands as written, and it is one of the most consequential changes to hit Indian buyer-supplier relationships in years. Whether you pay invoices or raise them, the 45-day clock is no longer just good etiquette — it is tax law.