A retailer reports $50 million pretax book income but only $30 million taxable income. Two accountants both cite ASC 740 and disagree by $2.1 million, all from a single valuation allowance judgment.
ASC 740 governs recognition, measurement, and disclosure of income taxes. The core principle: recognize both current taxes payable and future tax consequences of book-tax differences.
A temporary difference reverses in a future period, creating a future taxable or deductible amount. These produce deferred tax liabilities and assets.
A permanent difference never reverses. It affects the effective rate but creates no deferred tax balances.
Common permanent differences: tax-exempt municipal bond interest, nondeductible fines and penalties, life insurance proceeds on key employees, meals limitations.
KEY: If the book-tax difference eventually reverses, it is temporary. If it persists forever, it is permanent.
HIGH-FREQUENCY: A DTL arises when a temporary difference produces future taxable amounts. The most common source is depreciation: straight-line for books, MACRS for tax.
Other DTL sources: installment sales (full revenue on books, taxed as collected), prepaid expenses (deducted for tax when paid), unrealized gains on trading securities.
Common mistakes
- Treating permanent differences as temporary. Muni interest is never taxed and never reverses. It does not create a DTA or DTL. Computing a $4,200 DTA on $20,000 of muni interest is wrong.
- Reversing the depreciation direction. Tax depreciation exceeds book = lower taxable income now, higher later = DTL. Recording a DTA instead of a DTL reverses the answer.
- Forgetting the 80% NOL limitation. $500,000 NOL with $500,000 pre-NOL taxable income. Usable = 80% x $500,000 = $400,000. Taxable income = $100,000. Current tax = $21,000, not $0.
Bottom line
- Temporary differences create DTAs/DTLs; permanent differences only affect the effective tax rate
- DTL = future taxable amount (pay more later); DTA = future deductible amount (pay less later)
- Valuation allowance reduces DTAs when realization is not "more likely than not" (>50%); a three-year cumulative loss is strong negative evidence
- Rate changes remeasure ALL deferred balances at the new enacted rate in the period of enactment
Exam shortcut
When given pretax book income and several differences, work in layers: taxable income first, current tax, then ending DTAs/DTLs separately. If one answer equals pretax income times 21%, that is the trap for candidates ignoring temporary differences. DTL = "Pay Later." DTA = "Pay Less Later." Valuation allowance: three-year loss = strong negative evidence. The provision always combines current + deferred pieces.
The full lesson (about 1,891 words, 13 min read) adds 2 worked examples, all 6 common mistakes, a self-check, free in the app.
Learning objectives
- III.A1
- III.B1
- III.C1
- III.D1
- III.E1
- III.F1
- III.G1
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