When tax rates change, all deferred tax balances must be remeasured at the new rate. This creates sometimes-material gains or losses in P&L. This guide covers the mechanics, when to recognize the impact, and audit considerations.
Tax Rate Changes: When They Occur
Governments change tax rates periodically. Common scenarios:
- Statutory rate increase/decrease: Change in headline corporate tax rate (e.g., 19% →’ 25%)
- Temporary surcharge: Temporary tax on high earners or specific industries
- Phased changes: Rate changes over multiple years (e.g., 18% in 2025, 19% in 2026, 20% in 2027)
- Regional rate change: Sub-national rate changes (state/provincial)
IAS 12 Requirement: Enacted vs Substantively Enacted
Enacted Rate
Law has been passed; tax authority has full approval.
Substantively Enacted Rate
Law passes final legislative hurdle (awaits only formality, such as royal assent) but all substantive approval is complete.
Rule: Use the rate that is enacted or substantively enacted at the reporting date. If a rate change is proposed but not enacted, do NOT remeasure (too much uncertainty).
Remeasurement Mechanics
Step 1: Identify All Deferred Tax Balances
- Deferred tax liabilities (typically: fair value adjustments, accelerated depreciation)
- Deferred tax assets (typically: provisions, loss carryforwards)
Step 2: Recalculate at New Rate
Step 3: Recognize Change in P&L or OCI
- P&L items: Remeasurement gain/loss goes to P&L (line: "Impact of tax rate change")
- OCI items: Remeasurement gain/loss goes to OCI (matching the original transaction)
Worked Example: UK Tax Rate Increase
Scenario
Company ABC Ltd (UK): Year-end 31 Dec 2024
Current tax rate: 19% (enacted)
Announced change: Rate increases to 25% effective 1 April 2025 (substantively enacted Dec 2024)
Deferred Tax Position (Before Remeasurement)
| Item | Temp Diff £m | Old DTL/DTA @ 19% |
|---|---|---|
| PP&E fair value adjustment (DTL) | 100 | 19.0 |
| Provisions (DTA) | (40) | (7.6) |
| Net DTL | 60 | 11.4 |
Remeasurement at New 25% Rate
| Item | Temp Diff £m | New DTA/DTL @ 25% |
|---|---|---|
| PP&E fair value adjustment (DTL) | 100 | 25.0 |
| Provisions (DTA) | (40) | (10.0) |
| Net DTL | 60 | 15.0 |
P&L Impact
- Change in net DTL: £15.0m −’ £11.4m = £3.6m increase (cost to profit)
- P&L line: "Tax expense — impact of tax rate change" = £3.6m
- Effective tax rate impact: Higher tax expense despite no change in pre-tax profit
Balance Sheet
- Deferred tax liability (non-current): Increased from £11.4m to £15.0m
- Equity: Reduced by £3.6m (due to higher tax expense)
Phased Rate Changes
If rate change is phased (e.g., 25% in 2025, 26% in 2026, 27% in 2027), use the rate applicable when the temporary difference reverses:
Example: Phased Rate Change
- PP&E depreciation schedule: £10m per year for 10 years
- Reversal timeline: Years 2025— 2034 (10-year reversal)
- Tax rates by year: 2025: 25%, 2026: 26%, 2027: 27%, etc.
- Deferred tax calculation: Sum of (£10m × applicable year rate) / (1 + discount rate)^n
OCI Items: Deferred Tax Remeasurement
If a temporary difference relates to an OCI item (e.g., revaluation of property), remeasure deferred tax and recognize in OCI:
Example: Property Revaluation with Tax Rate Change
- Property revalued upward: £5m (recognized in OCI)
- Deferred tax on revaluation (@ 19%): £0.95m (recognized in OCI)
- Tax rate enacted to increase to 25%: Later in same year
- Remeasured deferred tax (@ 25%): £1.25m
- Adjustment: £1.25m −’ £0.95m = £0.3m (recognized in OCI, not P&L)
Audit Considerations
Common Audit Challenges
Challenge 1: Missed Rate Change
Finding: Tax rate enacted; deferred tax not remeasured.
Auditor action: Identify all deferred tax balances; recalculate at enacted rate; adjust P&L and OCI accordingly.
Challenge 2: Wrong Rate Used
Finding: Proposed rate change (not yet enacted) used; or old rate applied post-enactment.
Auditor action: Use only enacted or substantively enacted rates; restate to correct rate.
Challenge 3: OCI Items Misclassified
Finding: Deferred tax on OCI revaluation remeasured and adjustment sent to P&L (incorrect).
Auditor action: Reclassify adjustment to OCI (match the original transaction).
Real-Life Case Study: A Rate Change Hitting Deferred Balances
Scenario. A company carries a £2m deferred tax liability measured at 19%. A tax rise to 25% is substantively enacted before year end.
Treatment. Deferred tax is remeasured at the rate expected when the difference reverses, 25%. The liability jumps from £2m to about £2.63m, and the £0.63m increase is charged to P&L (unless the underlying item is in OCI/equity, where the remeasurement follows it).
Takeaway. Rate changes are recognised when substantively enacted, not when they take legal effect. A budget announcement can therefore move this year's deferred tax charge before a single pound of the new rate is actually paid.
Illustrative composite scenario for educational purposes. Figures are indicative and do not represent any specific company.
• IAS 12 Tax Loss Carryforwards: DTA Recognition & Utilization
• IAS 12 Valuation Allowances: DTA Realizability Assessment
• IAS 12 Deferred Tax on OCI: Recognizing Tax Effects in Other Comprehensive Income
• IAS 12 in M&A: Deferred Tax on Acquisition Fair Value Adjustments