CA
Tax Tutor
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Think of Section 40 as the IT department's veto list — expenses you may have genuinely paid, but which are still disallowed when computing business income. Two exam-critical areas dominate this section.

TDS defaults [Sections 40(a)(i) and 40(a)(ia)]

If you pay a resident any amount covered under TDS provisions — rent, professional fees, salary, commission, contract payments — and you either don't deduct TDS or you deduct it but don't deposit it by the ITR due date (31 October for companies/audit cases, 31 July for others), 30% of that payment is disallowed under Section 40(a)(ia). Note carefully: it's 30%, not 100%. Many students are still using older notes that said 100% — that changed via the Finance Act 2014 amendment. For non-residents [Section 40(a)(i)], the rule is far stricter: the entire payment (interest, royalty, fees for technical services) is 100% disallowed if TDS is not deducted or not paid by the due date. When do you get the deduction back? In the year you actually pay the TDS — even if that's a year later. The disallowance is temporary, not permanent. One important relief under 40(a)(ia): if the resident payee has already filed their return and declared that income (so tax has been paid at their end), the payer is deemed to have complied — no disallowance.

Income tax is never deductible [Section 40(a)(ii)]

Income tax, surcharge, cess paid on your own business profits are never an allowable expense. Neither is wealth tax. These come from post-tax income. Seems obvious, but this catches students in tricky MCQs and statement-based questions.

Firm-specific disallowances [Section 40(b)]

This part applies only to partnership firms. Two hard caps: (1) Interest to partners is capped at 12% per annum simple interest — anything above is disallowed. (2) Remuneration to working partners must be authorised by the partnership deed and within these slab limits: 90% of book profit on the first ₹3,00,000 (minimum ₹1,50,000 even in a loss), and 60% on the remaining book profit. Remuneration to non-working partners is 100% disallowed, no exceptions. Remember: book profit = net profit per P&L plus partner remuneration already deducted — don't forget to add it back. This section is tested as 4–8 mark questions almost every attempt.

📊 Worked example

Example 1 — Section 40(a)(ia): TDS default on resident payment

M/s Rajesh & Co. paid ₹10,00,000 as professional fees to Ms. Iyer (a resident CA) during FY 2024–25. TDS @ 10% (₹1,00,000) was deducted but deposited only on 15 December 2025, after the ITR due date of 31 October 2025.

| Step | Detail | Amount |

|------|--------|--------|

| TDS deducted? | Yes ✓ | — |

| Paid by ITR due date? | No ✗ | — |

| Disallowance = 30% × ₹10,00,000 | Section 40(a)(ia) | ₹3,00,000 |

| Deduction in FY 2025–26 (year TDS paid) | Proviso to 40(a)(ia) | ₹3,00,000 |

Final Answer: Disallowance for FY 2024–25 = ₹3,00,000. Allowed in FY 2025–26 when TDS is deposited.

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Example 2 — Section 40(b): Partnership firm remuneration limit

Sharma & Gupta LLP shows a net profit of ₹2,00,000 in its P&L after charging partner remuneration of ₹8,00,000 to two working partners. The partnership deed authorises this remuneration. Compute the disallowance under Section 40(b).

Step 1 — Compute book profit:

| | ₹ |

|--|--|

| Net profit as per P&L | 2,00,000 |

| Add: Partner remuneration charged | 8,00,000 |

| Book profit | 10,00,000 |

Step 2 — Maximum allowable remuneration (slab):

| Slab | Calculation | Amount |

|------|------------|--------|

| On first ₹3,00,000 @ 90% | 90% × ₹3,00,000 | ₹2,70,000 |

| On balance ₹7,00,000 @ 60% | 60% × ₹7,00,000 | ₹4,20,000 |

| Maximum allowed | | ₹6,90,000 |

Step 3 — Disallowance:

| | ₹ |

|--|--|

| Actual remuneration paid | 8,00,000 |

| Less: Maximum allowed | 6,90,000 |

| Disallowance u/s 40(b) | 1,10,000 |

⚠️ Common exam mistakes

  • Applying 100% disallowance for TDS default on resident payments — it's only 30% since the Finance Act 2014 amendment. The 100% rule applies only to non-residents under Section 40(a)(i). Double-check which clause the question is testing.
  • Forgetting to add back partner remuneration while computing book profit — book profit must include remuneration already deducted in P&L. Skipping this step understates the allowable limit and inflates your disallowance figure.
  • Treating income tax or cess paid as a deductible business expense — Section 40(a)(ii) explicitly bars this. Don't confuse it with GST or professional tax, which can be deductible under other provisions.
  • Allowing remuneration to non-working partners — Section 40(b)(i) disallows this completely. A partner must be actively engaged in conducting the firm's affairs to be a 'working partner'. Sleeping partners get nothing.
  • Treating the TDS disallowance as permanent — it is only deferred. The disallowed 30% (or 100%) is allowed as a deduction in the year the TDS is actually paid, under the proviso to the respective sub-clause. Always mention this in your answer for full marks.
📖 Bare Act text — Section 40, Income Tax Act 1961 (click to expand)
40. Amounts not deductible.—Notwithstanding anything to the contrary in 3[section 30 to 38], the following amounts shall not be deducted in computing the income chargeable under the head "Profits and gains of business or profession",—(a) in the case of any assessee— 4[(i) any interest (not being interest on a loan issued for public subscription before the 1st day of April, 1938), royalty, fees for technical services or other sum chargeable under this Act, which is payable,—(A) outside India; or (B) in India to a non-resident, not being a company or to a foreign company, on which tax is deductible at source under Chapter XVII-B and such tax has not been deducted or, after deduction, has not been paid 5[on or before the due date specified in sub-section (1) of section 139]: 6[Provided that where in respect of any such sum, tax has been deducted in any subsequent year, or has been deducted during the previous year but paid after the due date specified in sub-section (1) of section 139, such sum shall be allowed as a deduction in computing the income of the previous year in which such tax has been paid.] Explanation.—For the purposes of this sub-clause,—(A) "royalty" shall have the same meaning as in Explanation 2 to clause (vi) of sub-section (1) of section 9; (B) "fees for technical services" shall have the same meaning as in Explanation 2 to clause (vii) of sub-section (1) of section 9; (ia) 7[thirty per cent of any sum payable to a resident], on which tax is deductible at source under Chapter XVII-B and such tax has not been deducted or, after deduction, 8[has not been paid on or before the due date specified in sub-section (1) of section 139:] 9[Provided that where in respect of any such sum, tax has been deducted in any subsequent year, or has been deducted during the previous year but paid after the due date specified in sub-section (1) of section 139, 10[thirty per cent of] such sum shall be allowed as a deduction in computing the income of the previous year in which such tax has been paid:] 1[Provided further that where an assessee fails to deduct the whole or any part of the tax in accordance with the provisions of Chapter XVII-B on any such sum but is not deemed to be an assessee in default under the first proviso to sub-section (1) of section 201, then, for the purpose of this sub-clause, it shall be deemed that the assessee has deducted and paid the tax on such sum on the date of furnishing of return of income by the resident payee referred to in the said proviso.] Explanation.—For the purposes of this sub-clause,—(i) "commission or brokerage" shall have the same meaning as in clause (i) of the Explanation to section 194H; (ii) "fees for technical services" shall have the same meaning as in Explanation 2 to clause (vii) of sub-section (1) of section 9; (iii) "professional services" shall have the same meaning as in clause (a) of the Explanation to section 194J; (iv) "work" shall have the same meaning as in Explanation III to section 194C; 2[(v) "rent" shall have the same meaning as in clause (i) to the Explanation to section 194-I; (vi) "royalty" shall have the same meaning as in Explanation 2 to clause (vi) of sub-section (1) of section 9;] 3[(ib) any consideration paid or payable to a non-resident for a specified service on which equalisation levy is deductible under the provisions of Chapter VIII of the Finance Act, 2016, and such levy has not been deducted or after deduction, has not been paid on or before the due date specified in sub-section (1) of section 139: Provided that where in respect of any such consideration, the equalisation levy has been deducted in any subsequent year or has been deducted during the previous year but paid after the due date specified in sub-section (1) of section 139, such sum shall be allowed as a deduction in computing the income of the previous year in which such levy has been paid;]] 4[(ic) any sum paid on account of fringe benefit tax under Chapter XIIH;] (ii) any sum paid on account of any rate or tax levied on the profits or gains of any business or profession or assessed at a proportion of, or otherwise on the basis of, any such profits or gains. 5[Explanation 1.—For the removal of doubts, it is hereby declared that for the purposes of this sub-clause, any sum paid on account of any rate or tax levied includes and shall be deemed always to have included any sum eligible for relief of tax under section 90 or, as the case may be, deduction from the Indian income-tax payable under section 91.] 1[Explanation 2.—For the removal of doubts, it is hereby declared that for the purposes of this sub-clause, any sum paid on account of any rate or tax levied includes any sum eligible for relief of tax under section 90A;] 2[(iia) any sum paid on account of wealth-tax. Explanation.—For the purposes of this sub-clause, "wealth-tax" means wealth-tax chargeable under the Wealth-tax Act, 1957 (27 of 1957), or any tax of a similar character chargeable under any law in force in any country outside India or any tax chargeable under such law with reference to the value of the assets of, or the capital employed in, a business or profession carried on by the assessee, whether or not the debts of the business or profession are allowed as a deduction in computing the amount with reference to which such tax is charged, but does not include any tax chargeable with reference to the value of any particular asset of the business or profession;] 3[(iib) any amount—(A) paid by way of royalty, licence fee, service fee, privilege fee, service charge or any other fee or charge, by whatever name called, which is levied exclusively on; or (B) which is appropriated, directly or indirectly, from, a State Government undertaking by the State Government. Explanation.—For the purposes of this sub-clause, a State Government undertaking includes—(i) a corporation established by or under any Act of the State Government; (ii) a company in which more than fifty per cent of the paid-up equity share capital is held by the State Government; (iii) a company in which more than fifty per cent of the paid-up equity share capital is held by the entity referred to in clause (i) or clause (ii) (whether singly or taken together); (iv) a company or corporation in which the State Government has the right to appoint the majority of the directors or to control the management or policy decisions, directly or indirectly, including by virtue of its shareholding or management rights or shareholders agreements or voting agreements or in any other manner; (v) an authority, a board or an institution or a body established or constituted by or under any Act of the State Government or owned or controlled by the State Government;] 4[(iii) any payment which is chargeable under the head "Salaries", if it is payable—(A) outside India; or (B) to a non-resident, and if the tax has not been paid thereon nor deducted therefrom under Chapter XVII-B;] (iv) any payment to a provident or other fund established for the benefit of employees of the assessee, unless the assessee has made effective arrangements to secure that tax shall be deducted at source from any payments made from the fund which are chargeable to tax under the head "Salaries"; 1[(v) any tax actually paid by an employer referred to in clause (10CC) of section 10;] 2[(b) in the case of any firm assessable as such,—(i) any payment of salary, bonus, commission or remuneration, by whatever name called (hereinafter referred to as "remuneration") to any partner who is not a working partner; or (ii) any payment of remuneration to any partner who is a working partner, or of interest to any partner, which, in either case, is not authorised by, or is not in accordance with, the terms of the partnership deed; or (iii) any payment of remuneration to any partner who is a working partner, or of interest to any partner, which, in either case, is authorised by, and is in accordance with, the terms of the partnership deed, but which relates to any period (falling prior to the date of such partnership deed) for which such payment was not authorised by, or is not in accordance with, any earlier partnership deed, so, however, that the period of authorisation for such payment by any earlier partnership deed does not cover any period prior to the date of such earlier partnership deed; or (iv) any payment of interest to any partner which is authorised by, and is in accordance with, the terms of the partnership deed and relates to any period falling after the date of such partnership deed in so far as such amount exceeds the amount calculated at the rate of 3[twelve per cent.] simple interest per annum; or (v) any payment of remuneration to any partner who is a working partner, which is authorised by, and is in accordance with, the terms of the partnership deed and relates to any period falling after the date of such partnership deed in so far as the amount of such payment to all the partners during the previous year exceeds the aggregate amount computed as hereunder:— 4[(a) on the first Rs. 3,00,000 of the Rs. 1,50,000 or at the rate of 90 per cent. book-profit or in case of a loss of the book-profit, whichever is more; (b) on the balance of the book-profit at the rate of 60 per cent:] Provided that in relation to any payment under this clause to the partner during the previous year relevant to the assessment year commencing on the 1st day of April, 1993, the terms of the partnership deed may, at any time during the said previous year, provide for such payment. Explanation 1.—Where an individual is a partner in a firm on behalf, or for the benefit, of any other person (such partner and the other person being hereinafter referred to as "partner in a representative capacity" and "person so represented", respectively),—(i) interest paid by the firm to such individual otherwise than as partner in a representative capacity, shall not be taken into account for the purposes of this clause; (ii) interest paid by the firm to such individual as partner in a representative capacity and interest paid by the firm to the person so represented shall be taken into account for the purposes of this clause. Explanation 2.—Where an individual is a partner in a firm otherwise than as partner in a representative capacity, interest paid by the firm to such individual shall not be taken into account for the purposes of this clause, if such interest is received by him on behalf, or for the benefit, of any other person. Explanation 3.—For the purposes of this clause, "book-profit" means the net profit, as shown in the profit and loss account for the relevant previous year, computed in the manner laid down in Chapter IV-D as increased by the aggregate amount of the remuneration paid or payable to all the partners of the firm if such amount has been deducted while computing the net profit. Explanation 4.—For the purposes of this clause, "working partner" means an individual who is actively engaged in conducting the affairs of the business or profession of the firm of which he is a partner;] 1[(ba) in the case of an association of persons or body of individuals [other than a company or a co-operative society or a society registered under the Societies Registration Act, 1860 (21 of 1860), or under any law corresponding to that Act in force in any part of India], any payment of interest, salary, bonus, commission or remuneration, by whatever name called, made by such association or body to a member of such association or body. Explanation 1.—Where interest is paid by an association or body to any member thereof who has also paid interest to the association or body, the amount of interest to be disallowed under this clause shall be limited to the amount by which the payment of interest by the association or body to the member exceeds the payment of interest by the member to the association or body. Explanation 2.—Where an individual is a member of an association or body on behalf, or for the benefit, of any other person (such member and the other person being hereinafter referred to as "member in a representative capacity" and "person so represented", respectively),—(i) interest paid by the association or body to such individual or by such individual to the association or body otherwise than as member in a representative capacity, shall not be taken into account for the purposes of this clause; (ii) interest paid by the association or body to such individual or by such individual to the association or body as member in a representative capacity and interest paid by the association or body to the person so represented or by the person so represented to the association or body, shall be taken into account for the purposes of this clause. Explanation 3.—Where an individual is a member of an association or body otherwise than as member in a representative capacity, interest paid by the association or body to such individual shall not be taken into account for the purposes of this clause, if such interest is received by him on behalf, or for the benefit, of any other person.]
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