How does a change in the tax rate affect existing deferred tax assets and liabilities?

Yes, when the enacted tax rate changes, all existing deferred tax assets and liabilities must be remeasured at the new rate. The adjustment is recognized in the income statement (tax expense) in the period the rate change is enacted.

The principle: DTAs and DTLs represent future tax consequences. If the rate at which those consequences will be realized changes, the balances must be updated.

Formula:

Adjustment = Existing Deferred Tax Balance x (New Rate - Old Rate) / Old Rate

Or more directly:

New DTA/DTL = Temporary Difference x New Tax Rate Adjustment = New Balance - Old Balance

Worked Example:

Stonegate Industries has the following deferred tax balances based on a 30% tax rate:

Item	Temporary Difference	DTA/DTL at 30%
Accelerated depreciation	$2,000,000 (taxable)	DTL = $600,000
Warranty provision	$800,000 (deductible)	DTA = $240,000
Net		Net DTL = $360,000

Congress enacts a rate reduction from 30% to 25% effective next year.

Remeasurement:

Item	Old Balance (30%)	New Balance (25%)	Adjustment
DTL (depreciation)	$600,000	$500,000	-$100,000
DTA (warranty)	$240,000	$200,000	-$40,000
Net DTL	$360,000	$300,000	-$60,000

Income statement impact:

The net DTL decreased by $60,000. This means Stonegate recognizes a **$60,000 tax benefit** (reduction in tax expense) in the current period.

Breaking it down:

• DTL decrease of $100,000 → reduces tax expense (benefit)
• DTA decrease of $40,000 → increases tax expense
• Net effect: $100,000 -$40,000 = $60,000 benefit

Key analytical insights:

1. Companies with large DTLs benefit from rate cuts — the future tax burden shrinks, creating a one-time earnings boost
2. Companies with large DTAs are harmed by rate cuts — their future tax shields are worth less
3. Rate increases have the opposite effect

Real-world context: When the US Tax Cuts and Jobs Act reduced the corporate rate from 35% to 21% in 2017, companies with large DTLs (like utilities and industrial firms) saw massive one-time tax benefits, while companies with large DTAs (like banks with loan loss reserves) took write-downs.

Important nuances:

• Use the enacted rate, not the proposed rate. Adjustments only happen when the rate change is legally enacted
• If different temporary differences will reverse in different years with different rates (graduated rates), use the rate expected to apply when the difference reverses
• The adjustment is a one-time P&L event — it does not affect the effective tax rate in future periods (only the base rate changes going forward)

Exam tip: CFA Level II loves testing the direction of the adjustment. Remember: rate cut + net DTL = benefit; rate cut + net DTA = expense. Draw the T-accounts if you get confused.

For more deferred tax scenarios, check our CFA Level II question bank.