Section 43 of the Income-tax Act, 2025 — Taxation of Foreign Exchange Fluctuation (Forex Gain/Loss)

In plain language

What Section 43 actually deals with

Section 43 of the Income-tax Act, 2025 is titled "Taxation of foreign exchange fluctuation." It is not a "business deductions" clause in the ordinary sense — it is a special computation rule that tells you how to tax a gain or claim a loss that arises purely because the rupee value of a foreign-currency transaction changes between two dates. It is the direct successor to Section 43AA of the old Income-tax Act, 1961, and it takes effect from 1 April 2026, applying from tax year 2026-27 onward.

The core rule (sub-section 1) is simple: any gain or loss arising on account of change in foreign exchange rates on foreign currency transactions shall be treated as income or loss, and shall be computed as per the Income Computation and Disclosure Standards (ICDS) notified under Section 276(2) of the 2025 Act. The relevant standard is ICDS-VI (Effects of Changes in Foreign Exchange Rates).

Who it applies to

• Any business or profession dealing in foreign currency — importers, exporters, IT/software exporters, companies with foreign loans (ECBs), those with overseas branches or subsidiaries, and anyone holding forex assets or liabilities.
• All assessees, regardless of accounting framework — whether you follow Indian GAAP, Ind AS or IFRS, the tax computation must follow ICDS-VI. Book treatment and tax treatment can therefore differ.
• It does not normally affect salaried individuals or people with only Indian-rupee income.

What transactions are covered (sub-section 2)

The rule applies to all foreign currency transactions, expressly including:

• Monetary items and non-monetary items — e.g. foreign-currency loans, trade receivables and payables (monetary), versus fixed assets, inventory and investments (non-monetary).
• Translation of financial statements of foreign operations — overseas branches and subsidiaries.
• Forward exchange contracts — hedging and trading contracts.
• Foreign currency translation reserves.

Key conditions and the "subject to Section 42" carve-out

• Section 43 is subject to Section 42 (the successor to old Section 43A). Where a forex difference on a capital asset acquired from outside India is capitalised — added to or reduced from the actual cost of the asset under Section 42 — that same difference is excluded from Section 43. This prevents double treatment: you cannot both adjust the asset's cost and separately claim the forex swing as revenue income/loss.
• Both realised and unrealised (mark-to-market) differences are recognised for tax as per ICDS-VI, subject to that standard's rules. This is why year-end restatement of monetary items creates taxable income or an allowable loss even before actual settlement.

How it interacts with related sections

• Section 42 (old 43A): capitalisation of forex differences on imported capital assets — takes priority over Section 43.
• Section 276(2): the enabling power under which ICDS are notified; Section 43 borrows its computation method from here.
• Section 26 / Section 33 (general business income and general deductions): Section 43 is a specific timing-and-measurement rule sitting on top of the normal "profits and gains of business or profession" computation.

Practical implications

• Keep separate workings: book forex gain/loss vs ICDS forex gain/loss, and reconcile the difference in your tax computation.
• Restate all monetary foreign-currency assets and liabilities at the closing rate on the last day of the year; the difference is taxable or deductible.
• Where a forex loss relates to acquiring an imported capital asset, check whether it must be capitalised under Section 42 instead of claimed as a revenue loss.
• A genuine forex loss on revenue account is generally an allowable business loss and is not a "contingent" or notional loss once ICDS conditions are met.