Income tax expense reported on the income statement rarely equals the cash a company hands to the tax authority. The gap, driven by temporary timing differences and permanent disallowances, lives on the balance sheet as deferred tax assets and liabilities.
Companies live in two parallel accounting worlds. The financial reporting world produces accounting profit (pretax income) using generally accepted accounting principles (GAAP) or IFRS. The tax world produces taxable income using the tax code. The two systems use different depreciation lives, different revenue timing, and different allowable expenses.
KEY: Accounting profit drives reported earnings. Taxable income drives the cash tax bill. They almost never match.
Taxes payable is the legal liability owed to the tax authority for the period. It equals taxable income times the statutory rate. Income tax expense is the GAAP/IFRS charge on the income statement. The connector:
Temporary differences are timing gaps that reverse in future periods. Depreciation is the classic example. A company books straight-line depreciation for financial reporting and accelerated depreciation for tax.
Common mistakes
- Confusing income tax expense with taxes payable. Tax expense is the GAAP charge. Taxes payable is the legal liability. They differ by the change in deferred items. Trap: assuming the income statement number equals the check written to the tax authority.
- Creating a DTL/DTA for a permanent difference. Municipal interest, fines, and certain dividend deductions never reverse. They flow through the effective rate reconciliation only. Trap: setting up a DTA for non-deductible fines.
- Reversing the DTL/DTA trigger. DTL arises when book income exceeds taxable income today (pay more tax later). DTA arises when book income is below taxable income today (pay less tax later). Trap: assigning a DTA to accelerated tax depreciation, which actually creates a DTL.
Bottom line
- Accounting profit follows GAAP/IFRS; taxable income follows the tax code. Income tax expense = taxes payable + change in DTL − change in DTA.
- Temporary differences reverse and create DTL/DTA. Permanent differences never reverse and only affect the effective tax rate.
- DTL when book income exceeds taxable income (deferred outflow). DTA when book income is below taxable income (deferred inflow, if realizable).
- A valuation allowance reduces a DTA when realization is doubtful; a rising allowance signals a weakening profitability outlook.
Exam shortcut
For DTL vs. DTA direction, remember "Book High = DTL, Book Low = DTA" relative to taxable income. For permanent vs. temporary, ask whether the item ever reverses. If never, it touches only the effective rate. For the three rates, remember SEC: Statutory (law), Effective (P&L), Cash (cash flow). When the question asks whether to treat a DTL as debt or equity, the trigger is whether reversal is realistically expected.
The full lesson (about 2,273 words, 15 min read) adds 2 worked examples, all 6 common mistakes, a self-check, free in the app.
Learning objectives
- analysis of income taxes
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