What is the tax arbitrage rule on interest expense?

The tax arbitrage rule under NIRC Section 34(B)(1) reduces a taxpayer's deductible interest expense by an amount equal to 20% of interest income earned in the same taxable year that was already subjected to final withholding tax, such as bank deposit interest.

Why does the BIR limit the interest expense deduction this way?

Without the limitation, a business could borrow at interest, deduct the full interest expense against income taxed at the regular corporate or individual rate, while simultaneously earning interest income that is taxed only at a lower final withholding rate — effectively arbitraging the gap between the two tax rates. The 20% reduction closes that gap.

Does the interest expense limitation apply even without an intentional tax scheme?

Yes. Revenue Memorandum Circular No. 19-2024 clarifies that the reduction applies whenever a taxpayer has both deductible interest expense and interest income subjected to final tax in the same taxable year, regardless of whether the loan and the interest-earning investment were connected or timed as a deliberate tax arbitrage scheme.

Does the interest expense limitation apply to all corporations?

The reduction has limited or no practical effect on corporations taxed at a rate equal to the final tax rate on their interest income, because there is no rate gap left to arbitrage. It matters most where a meaningful difference remains between the taxpayer's regular income tax rate and the final tax rate on the interest income earned.

Where is the interest expense limitation reported on a return?

There is no separate BIR form for the interest arbitrage adjustment — it is computed as part of preparing the interest expense deduction reported on the taxpayer's regular annual or quarterly income tax return (BIR Form 1701/1701Q for individuals, 1702/1702Q for corporations), reducing the interest expense line before it is claimed.

Why Is Your Interest Expense Deduction Reduced? The BIR's Tax Arbitrage Rule Under NIRC Section 34(B)(1)

If a business deducts interest expense on a loan and also earns interest income that was subjected to final withholding tax in the same year — most commonly bank deposit interest — NIRC Section 34(B)(1) requires cutting the deductible interest expense by 20% of that final-tax interest income before claiming it. This “tax arbitrage” limitation catches many taxpayers off guard because it applies automatically, not just when a loan and a deposit were deliberately paired to reduce tax.

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What is the tax arbitrage problem this rule addresses? #

The limitation exists because, without it, a taxpayer could deduct interest expense at the full regular income tax rate while the interest income it effectively funds is taxed at a lower final rate, capturing the rate difference as a tax benefit rather than a real economic cost. A common illustration: a company borrows funds at interest (deductible against income taxed up to the regular corporate rate) while placing other cash in an interest-bearing bank deposit (taxed at a flat 20% final rate, regardless of the company’s regular tax bracket). Left unchecked, the company effectively converts ordinary income into a lower-taxed category by running both transactions side by side. NIRC Section 34(B)(1), first implemented through Revenue Regulations No. 13-2000, addresses this by mechanically reducing the deductible interest expense whenever both conditions are present in the same year.

How is the reduction computed? #

The deductible interest expense is reduced by an amount equal to 20% of the interest income the taxpayer earned in the same taxable year that was already subjected to final withholding tax. The mechanics:

Item	Amount
Gross interest expense on business indebtedness	Full amount actually paid or incurred
Interest income subjected to final tax (e.g., bank deposit interest)	Full amount earned during the same year
Reduction to interest expense	20% × interest income subjected to final tax
Deductible interest expense	Gross interest expense − reduction

Revenue Memorandum Circular No. 19-2024, issued by the BIR to clarify recurring questions on this rule, confirms that the 20% reduction applies whenever both a deductible interest expense and final-tax interest income exist in the same taxable year — it does not require proof that the taxpayer set up the loan and the deposit as a coordinated scheme, and it applies regardless of when each transaction started.

Worked example #

A trading corporation pays ₱800,000 in interest expense during the year on a working-capital loan, and separately earns ₱150,000 in interest income on its operating bank deposits, already subjected to the standard 20% final withholding tax at source.

Interest income subjected to final tax: ₱150,000
Reduction: 20% × ₱150,000 = ₱30,000
Deductible interest expense: ₱800,000 − ₱30,000 = ₱770,000

The company still deducts the large majority of its interest expense — the rule trims the deduction proportionally to the final-tax interest income earned, rather than disallowing interest expense altogether.

When does the limitation matter less? #

The reduction has little or no practical bite for a corporation whose regular income tax rate leaves no meaningful gap against the final tax rate on its interest income — the arbitrage the rule targets shrinks or disappears when the two rates converge. Where a real rate gap remains, however, taxpayers preparing BIR Form 1702Q or BIR Form 1701Q with both business borrowing and interest-bearing deposits should apply this reduction before finalizing the interest expense line, alongside the other ordinary and necessary business expense rules that govern deductibility generally.

Summary #

NIRC Section 34(B)(1)’s tax arbitrage rule automatically reduces deductible interest expense by 20% of any interest income the same taxpayer earned and had subjected to final withholding tax in the same year, as clarified by RMC No. 19-2024 — it applies whether or not the loan and the deposit were intentionally connected. Businesses carrying both interest-bearing debt and interest-bearing deposits should check this adjustment before finalizing their annual or quarterly interest expense deduction.