Deferred tax on defined benefit pension schemes exists because the pension cost shown in the financial statements almost never equals the pension contribution the tax authority allows as a deduction in the same year. Accounting standards measure the pension expense from an actuary’s estimate of the future obligation; tax law generally recognizes cash contributions when they are actually paid into the plan. That gap is a temporary difference, and deferred tax is how the balance sheet carries the future tax consequences of closing it.
Why the Timing Difference Arises
A defined benefit scheme promises employees a specific retirement payout tied to salary and service. Accounting standards require the employer to estimate the present value of those future payments and put the net obligation or surplus on the balance sheet. Each year’s pension expense reflects service cost, interest on the liability, and updates to actuarial assumptions about mortality and salary growth.
Tax authorities largely ignore those actuarial estimates. In the United States, IRC Section 404 ties the employer’s deduction to the amount actually contributed to the plan rather than the accounting charge. So the income statement might show a large pension expense in a year when the cash contribution was small, or the reverse. Over the life of the plan the two totals converge; in any single year they diverge, sometimes sharply. That divergence is the raw material for deferred tax. When the accounting expense exceeds the deductible contribution, a deferred tax asset builds up for the relief expected on later, larger contributions. When contributions run ahead of the expense, a deferred tax liability forms instead.
Deficit Produces an Asset, Surplus Produces a Liability
The starting point for recognition is the comparison between the pension figure on the balance sheet and its tax base. Under both IFRS (IAS 12) and US GAAP (ASC 740), a deferred tax balance is required whenever a temporary difference exists between those two amounts. The tax base is usually the cumulative contributions that have already been deducted; the carrying amount is the actuarial measure of the net obligation or surplus.
A pension deficit, where the obligation exceeds plan assets, typically produces a deferred tax asset. The employer will need to make future contributions to close the gap, those contributions will be tax-deductible, and the asset represents the expected tax saving. A surplus works in reverse: plan assets above the obligation may eventually be taxable when the employer benefits from them, so a deferred tax liability arises.
FRS 102 Section 29, which governs deferred tax under UK GAAP, reaches the same result through the language of timing differences between when items hit the income statement and when they appear in the tax computation.1ICAEW. Deferred Tax Under FRS 102 The principle across frameworks is the same: match the tax consequence to the period that recognized the related economic event.
Which Tax Rate to Use
Deferred tax balances are measured at the tax rate expected to apply when the timing difference reverses. Both IFRS and US GAAP require a rate that has been enacted (or, under IFRS, substantively enacted) by the balance sheet date. In the United States the federal corporate rate has been a flat 21% since the Tax Cuts and Jobs Act took effect in 2018, and that rate remains in place for 2026.2Legal Information Institute. Tax Cuts and Jobs Act of 2017 State corporate income taxes, ranging from zero to roughly 11.5% depending on the jurisdiction, feed into the blended rate most companies use.
When a legislature changes the rate, existing deferred tax balances must be remeasured immediately. A rise from 21% to 25% would make every pension-related deferred tax asset more valuable, because the future deductions it represents would save more tax; a deferred tax liability would grow for the same reason. The remeasurement gain or loss flows through the income statement or through other comprehensive income in the period of enactment, not the period the rate takes effect. Even a few percentage points wrong can produce a material misstatement for a company with a large scheme.
How the Deduction Cap and Minimum Funding Drive the Gap
The mismatch between accounting expense and tax deduction is not accidental. It comes from statutory rules that cap the deduction and floor the required contribution.
Under IRC Section 404(o), the maximum deductible contribution to a single-employer defined benefit plan is the greater of two figures: the funding target plus target normal cost plus a “cushion amount” (less plan assets), or the minimum required contribution under IRC Section 430.3Office of the Law Revision Counsel. 26 USC 404 Deduction for Contributions of an Employer to an Employees Trust or Annuity Plan and Compensation Under a Deferred-Payment Plan The cushion amount is 50% of the funding target plus adjustments for expected future compensation increases. A contribution above the deductible ceiling is not lost, but the excess only becomes deductible in later years, and IRC Section 4972 imposes a 10% excise tax on nondeductible contributions.4Office of the Law Revision Counsel. 26 USC 4972 Tax on Nondeductible Contributions to Qualified Employer Plans
At the other end, IRC Section 430 sets the minimum contribution.5Office of the Law Revision Counsel. 26 USC 430 Minimum Funding Standards for Single-Employer Defined Benefit Pension Plans Where plan assets fall short of the funding target, the required contribution is the target normal cost plus shortfall and waiver amortization charges. Where assets meet or exceed the funding target, the required contribution is target normal cost less the excess, floored at zero. A deeply underfunded plan therefore forces larger contributions over the amortization period, and those contributions drive the timing of tax deductions.
Contributions count for a tax year if deposited by the due date of the return, including extensions, so an employer can file and still make a deductible contribution for that year before the extended deadline. Between the Section 404 ceiling and the Section 430 floor sits a corridor, and where the actual contribution lands inside that corridor, relative to the accounting expense, determines whether the deferred tax balance grows or shrinks.
Where the Deferred Tax Movement Lands
Not every change in the pension-related deferred tax balance hits the same place. The tax effect follows the underlying item. Pension gains or losses recognized in profit or loss carry their deferred tax through profit or loss; pension items recognized in other comprehensive income carry their deferred tax through OCI.
Under IAS 19, remeasurements of the net defined benefit obligation, including actuarial gains and losses from changed assumptions and the difference between actual and expected returns on plan assets, are recognized in OCI and never reclassified to profit or loss.6IFRS Foundation. IAS 19 Employee Benefits ASC 715 takes a similar path under US GAAP, sending gains and losses not immediately recognized in net periodic pension cost to OCI. Current service cost and net interest expense, by contrast, sit in the income statement, and their deferred tax effects sit in the tax line.
The split matters for anyone reading an effective tax rate. A year with heavy actuarial losses can produce a large deferred tax asset movement without touching the income statement tax charge, because the movement is buried in OCI. Ignoring that distinction makes the tax line look erratic when the underlying operations have not changed.
Testing Whether the Asset Is Actually Recoverable
A deferred tax asset is only worth showing if the company can use it. Under ASC 740, a valuation allowance must reduce the asset when it is “more likely than not” (a likelihood greater than 50%) that some or all of it will not be realized. IAS 12 sets a similar bar in different words: deferred tax assets are recognized only to the extent it is “probable” that taxable profits will be available to absorb the deductible temporary differences.
For a pension deficit, the question is whether the employer will earn enough taxable income in future years to benefit from the deductions when catch-up contributions are made. A large deficit against declining revenues is the classic warning sign. The assessment draws on historical profitability, existing contracts, and realistic long-term projections. If the evidence does not support full recoverability, the asset is written down through a valuation allowance, reducing net assets directly.
A separate constraint applies to surpluses under IFRS. IAS 19 caps the recognized surplus at the “asset ceiling,” defined as the present value of economic benefits available to the employer as refunds from the plan or reductions in future contributions.7IFRS Foundation. IFRIC 14 IAS 19 The Limit on a Defined Benefit Asset Minimum Funding Requirements and Their Interaction Any surplus above what the employer can realistically extract is not recognized, and the deferred tax liability tied to that unrecognizable portion falls away with it.
How the Reversion Excise Tax Reshapes a Surplus
When a plan terminates with a surplus and the employer takes the excess back, the tax cost is not limited to ordinary income tax. IRC Section 4980 imposes a default excise tax of 50% on any employer reversion from a qualified plan.8Office of the Law Revision Counsel. 26 USC 4980 Tax on Reversion of Qualified Plan Assets to Employer That rate drops to 20% if the employer establishes a qualified replacement plan or amends the terminating plan to provide statutorily specified benefit increases.
The effect on deferred tax measurement is easy to miss. A surplus on the balance sheet can look like a straightforward future taxable amount, but the after-tax economic benefit depends on how the surplus will actually be accessed. If the realistic route out is a reversion carrying the 50% excise tax on top of ordinary income tax, the value the employer will keep is a small fraction of the surplus. The deferred tax balance associated with the surplus needs to reflect the likely reversion tax, not just the headline income tax rate.