Ch7. Tax Accounting Fundamentals — Corporate Income Tax and Tax Adjustments

What Is Tax Accounting?

Tax Accounting: Accounting performed under tax law regulations to calculate taxable income for tax reporting purposes.

Financial accounting follows IFRS/GAAP; tax accounting follows tax law (the Internal Revenue Code and related regulations). The differences between these two sets of rules give rise to book-to-tax adjustments.

Structure of Corporate Income Tax

Taxable Income = Gross Income − Allowable Deductions

Corporate Tax = Taxable Income × Tax Rate

Taxable Income = Book Income
                 + Permanent Differences (items always treated differently)
                 + / − Temporary Differences (timing differences that reverse)
                 − Tax Credits and Deductions

US Federal Corporate Tax Rate

Taxable Income	Rate
All taxable income	Flat 21% (post-Tax Cuts and Jobs Act 2017)

Note: State corporate income taxes vary, typically 0%–12%. The combined federal + state effective rate is typically 25%–29% for most US corporations.

Financial Accounting vs. Tax Accounting: Key Differences

Item	Financial Accounting	Tax Accounting
Depreciation	Company’s chosen method and life	IRS-prescribed MACRS schedules
Entertainment / Meals	Fully expensed	50% deductible limit (meals); entertainment largely non-deductible
Charitable Contributions	Fully expensed	Deductible up to 10% of taxable income for corporations
Allowances & Reserves	Based on reasonable estimates	Must meet specific tax requirements

Book-to-Tax Adjustments

The process of converting financial accounting income to taxable income.

Taxable Income = Book Income (pre-tax net income)
                 + Permanent Add-backs (e.g., non-deductible expenses such as fines)
                 − Permanent Exclusions (e.g., tax-exempt interest income)
                 + Temporary Timing Differences (e.g., tax depreciation < book depreciation)
                 − Temporary Timing Differences (e.g., tax depreciation > book depreciation)

Common adjustment items:

Meals/entertainment over the limit: Non-deductible (permanent difference)
Excess MACRS vs. straight-line depreciation: Temporary timing difference
Fines and penalties: Non-deductible (permanent add-back)
Tax-exempt interest (e.g., municipal bonds): Permanent exclusion

Deferred Taxes

Future tax assets or liabilities arising from temporary differences between book and tax accounting.

Temporary Difference: A difference in the current period that will reverse in a future period

Example: Book depreciation $20,000
         Tax depreciation (MACRS)  $30,000
→ Tax deduction is larger, reducing current-year tax payable
→ This difference will reverse in future years → Deferred Tax Liability recognized

Deferred Tax Asset (DTA): Taxes paid or recorded now that reduce future tax liability (an asset) Deferred Tax Liability (DTL): Future taxes owed because of lower tax expense now (a liability)

Tax Credits and Incentives

Type	Description
Research & Development (R&D) Tax Credit	Credit for a percentage of qualified research expenses
Work Opportunity Tax Credit (WOTC)	Credit for hiring from targeted groups facing employment barriers
Investment Tax Credit	Credit for investments in certain equipment or renewable energy
Foreign Tax Credit	Prevents double taxation of foreign-sourced income

Key Concept Cards

Permanent vs. Temporary Differences ★★★★★ : Permanent differences (e.g., non-deductible fines) never reverse and create no deferred tax. Temporary differences (e.g., depreciation timing) reverse over time and create deferred tax assets or liabilities. Memory tip: Permanent = no deferred tax; Temporary = creates deferred tax

Deferred Tax ★★★★☆ : The future tax effect of temporary differences between book and tax accounting. Results in a deferred tax asset (taxes will be lower in the future) or liability (taxes will be higher). Memory tip: Temporary difference → Deferred Tax Asset or Liability

Non-Deductible Expenses ★★★★☆ : Costs recorded as book expenses that the tax code does not allow as deductions. They permanently increase taxable income above book income. Memory tip: Non-deductible = tax increase adjustment

Practice Quiz

Q. Book income is $100,000. Non-deductible meals and entertainment is$ 5,000, and tax-exempt municipal bond interest is $3,000. What is taxable income?

$100,000 +$ 5,000 (permanent add-back) − $3,000 (permanent exclusion) =$ 102,000.

Q. Give an example of when a deferred tax asset would be recorded.

When book expenses exceed tax deductions in the current period (e.g., an allowance for doubtful accounts recognized for book purposes but not yet deductible for tax). Taxes paid currently are higher than what is economically owed, so a deferred tax asset captures the future tax savings.

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