What is US GAAP — Core Rule
US GAAP (Generally Accepted Accounting Principles) is the authoritative financial reporting framework issued by the FASB (Financial Accounting Standards Board) and codified in the FASB ASC; it differs fundamentally from IFRS in recognition thresholds, measurement bases, and presentation requirements, making year-end reconciliation and dual-reporting mandatory for multinational entities.
How What is US GAAP Works
What is US GAAP? A Complete Guide begins with understanding that US GAAP is principles-based but rules-heavy, whereas IFRS is more principles-based with greater judgment. Key structural differences:
- Revenue Recognition: Under ASC 606, revenue is recognized when control of promised goods or services transfers to the customer (ASC 606-10-25-1). IFRS 15 uses identical language, but US GAAP provides more implementation guidance and carve-outs (e.g., ASC 606-10-15-2 for contract modifications). Practitioners applying US GAAP must use the five-step model with extensive bright-line tests.
- Lease Accounting: ASC 842 requires lessees to recognize right-of-use (ROU) assets and lease liabilities on the balance sheet for most leases (ASC 842-20-25-1), mirroring IFRS 16. However, US GAAP permits the practical expedient to not reassess lease classification for short-term leases under 12 months (ASC 842-20-25-7), while IFRS allows reassessment only in narrow circumstances.
- Business Combinations: ASC 805 mandates acquisition accounting with goodwill measured as residual consideration; IFRS 3 is largely aligned but permits alternative measurement of non-controlling interests at fair value or proportionate share (ASC 805-20-30-1 vs. IFRS 3 para 32). US GAAP does not permit the latter.
- Impairment Testing: ASC 360 (property, plant, equipment) and ASC 350 (intangibles) use a two-step impairment model (recoverability test, then loss measurement), while IAS 36 uses a one-step approach comparing carrying value to recoverable amount (ASC 360-10-35-19). This creates material differences in timing and quantum of impairment charges.
- Development Costs: ASC 730 capitalizes software development costs once technological feasibility is established (ASC 730-10-25-1); IAS 38 capitalizes development costs once technical and commercial feasibility criteria are met, resulting in earlier capitalization under IFRS in many IT projects.
- Presentation and Disclosure: ASC 210 (balance sheet) requires classification into current/non-current assets and liabilities; IFRS allows liquidity-based presentation in certain industries. Segment reporting under ASC 280 uses the management approach but requires quantitative thresholds (10% of revenue/profit/assets); IFRS 8 mirrors this but with less prescriptive guidance (ASC 280-10-50-1).
What is US GAAP — Practical Example
A US-traded company acquires an intangible software asset for $5M cash with an expected useful life of 5 years. Year 1 revenue impact differs under US GAAP and IFRS due to amortization method availability and impairment triggers.
US GAAP Treatment (ASC 350-30-35-1)
| Account | Dr | Cr |
|---|
| Intangible Asset – Software | 5,000,000 | |
| Cash | | 5,000,000 |
Year 1 amortization (straight-line, 5 years): $1,000,000.
| Amortization Expense | 1,000,000 | |
|---|
| Accumulated Amortization – Software | | 1,000,000 |
Impairment testing: If undiscounted future cash flows ($3.8M) fall below carrying value ($4.0M), a two-step impairment loss is recognized (ASC 360-10-35-19).
IFRS Treatment (IAS 38)
Identical initial recognition ($5M). However, IFRS permits revaluation to fair value post-acquisition if an active market exists (IAS 38.75), whereas US GAAP prohibits upward revaluation of intangibles (ASC 350-20-35-2). Year 1 amortization is $1.0M (same). Impairment uses one-step recoverable amount model (fair value less costs to sell, or value in use). If recoverable amount is $3.9M, impairment loss is $0.1M—potentially lower than US GAAP depending on discount rate assumptions.
Net Impact: A $100k–$500k difference in Year 1 pre-tax income and balance sheet carrying values, requiring full reconciliation in footnote disclosures.
What is US GAAP — Common Pitfalls
- Lease Classification Errors: Practitioners misapply ASC 842 practical expedients, especially the 12-month short-term lease exemption (ASC 842-20-25-7), by not measuring the lease term correctly (including renewal options the lessee is reasonably certain to exercise). This results in unrecorded ROU assets and lease liabilities.
- Revenue Recognition Timing: Under ASC 606-10-25-1, control transfer is frequently misjudged in contracts with acceptance clauses or performance obligations spread over time. Auditors often find revenue recognized too early when customer acceptance is a genuine condition precedent, not merely administrative.
- Goodwill Impairment Understatement: ASC 350-20-35-3 requires annual goodwill impairment testing using a single-step model (fair value vs. carrying value). Many entities defer testing or use stale projections, missing declines in fair value that trigger impairment under Step 1 (no Step 2 recoverability hurdle as in property/plant equipment).
What is US GAAP — Key Paragraphs
- ASC 606-10-25-1: Revenue recognition control transfer principle.
- ASC 842-20-25-1: Right-of-use asset and lease liability recognition.
- ASC 350-20-35-3: Goodwill impairment single-step test.
- ASC 805-20-30-1: Business combination acquisition accounting and goodwill measurement.
- ASC 360-10-35-19: Long-lived asset impairment recoverability and measurement.
- ASC 280-10-50-1: Segment reporting quantitative thresholds (10% tests).
