GAAP (Generally Accepted Accounting Principles): Definition & Guide
Why GAAP Matters
Without a common rulebook, every company could account for transactions however it pleased — making it impossible to compare Apple’s financials to Microsoft’s, or to spot manipulation. GAAP solves this by creating a shared language. When a company says its revenue was $10 billion under GAAP, investors know exactly what that means: revenue recognized according to specific, well-defined standards.
All publicly traded companies in the United States are required by the SEC to file financial statements prepared in accordance with GAAP. Private companies aren’t legally required to follow GAAP, but most do — especially if they have investors, lenders, or plans to go public.
Who Sets GAAP?
The Financial Accounting Standards Board (FASB) is the independent organization responsible for establishing and updating GAAP. The FASB issues Accounting Standards Updates (ASUs) that modify the FASB Accounting Standards Codification — the single authoritative source of U.S. GAAP.
The SEC has the legal authority to set accounting standards for public companies but has historically delegated that role to the FASB. The SEC reviews and enforces compliance but generally doesn’t write the rules itself.
Core Principles of GAAP
GAAP is built on a set of foundational principles that guide how transactions are recorded and reported:
| Principle | What It Means |
|---|---|
| Revenue Recognition | Revenue is recorded when earned and realizable — not necessarily when cash is received (see accrual accounting) |
| Matching Principle | Expenses are recorded in the same period as the revenues they help generate (depreciation and amortization are direct applications) |
| Historical Cost | Assets are generally recorded at their original purchase price, not current market value |
| Full Disclosure | All material information must be disclosed in financial statements or footnotes |
| Conservatism | When in doubt, recognize losses early and defer gains — err on the side of understating rather than overstating |
| Consistency | Companies should use the same accounting methods period to period, disclosing any changes |
| Materiality | Only information significant enough to influence decision-making needs to be reported |
| Going Concern | Financial statements assume the company will continue operating indefinitely |
The Three Financial Statements Under GAAP
GAAP requires companies to produce three core financial statements, each following specific standards for recognition, measurement, and disclosure:
| Statement | What It Shows | Key GAAP Considerations |
|---|---|---|
| Income Statement | Revenue, expenses, and profit over a period | Revenue recognition rules (ASC 606), expense matching, depreciation methods |
| Balance Sheet | Assets, liabilities, and equity at a point in time | Historical cost vs. fair value, goodwill impairment testing, lease accounting |
| Cash Flow Statement | Cash inflows and outflows across operating, investing, and financing activities | Interest paid classified as operating; indirect method most common |
GAAP vs. Non-GAAP Measures
Companies frequently report both GAAP and “non-GAAP” (or “adjusted”) results. Non-GAAP metrics strip out items management considers non-recurring or non-operational — stock-based compensation, restructuring charges, acquisition-related costs, amortization of acquired intangibles, and similar items.
Non-GAAP measures can be genuinely useful for understanding a business’s ongoing performance. But they can also be used to paint a rosier picture than reality. The SEC requires that non-GAAP results be presented alongside GAAP figures with a clear reconciliation.
GAAP vs. IFRS: Key Differences
The other major accounting framework is IFRS (International Financial Reporting Standards), used in over 140 countries. Here are the most important differences:
| Area | U.S. GAAP | IFRS |
|---|---|---|
| Standards body | FASB | IASB (International Accounting Standards Board) |
| Approach | Rules-based — detailed, specific guidance | Principles-based — broader framework, more judgment |
| Inventory methods | FIFO, LIFO, and weighted average allowed | LIFO is prohibited |
| Goodwill | Not amortized; tested for impairment annually | IASB considering reintroducing amortization |
| Asset revaluation | Generally not permitted (historical cost) | Allowed for certain asset classes |
| Development costs | Generally expensed as incurred | Capitalized when criteria are met |
| Geographic reach | United States (and SEC filers) | 140+ countries worldwide |
For a full breakdown, see our GAAP vs. IFRS comparison.
Common GAAP Standards You’ll Encounter
| Standard | Topic | Why It Matters |
|---|---|---|
| ASC 606 | Revenue recognition | Governs when and how revenue is recorded — foundational for every company |
| ASC 842 | Leases | Brought most operating leases onto the balance sheet |
| ASC 350 | Goodwill and intangibles | Defines impairment testing and amortization rules |
| ASC 820 | Fair value measurement | Establishes the fair value hierarchy (Level 1, 2, 3) |
| ASC 740 | Income taxes | Governs deferred tax assets and liabilities, tax provision calculations |
Key Takeaways
- GAAP is the mandatory accounting framework for U.S. public companies, set by the FASB and enforced by the SEC.
- Core principles include revenue recognition, matching, historical cost, conservatism, and full disclosure.
- GAAP is rules-based with specific guidance; IFRS is principles-based with more room for judgment.
- Non-GAAP metrics are common but should always be reconciled to GAAP — watch for widening gaps between the two.
- Major standards like ASC 606 (revenue) and ASC 842 (leases) directly affect how you read financial statements.
Frequently Asked Questions
Is GAAP required for all companies?
All U.S. publicly traded companies must follow GAAP when filing with the SEC. Private companies are not legally required to use GAAP, but many do because lenders, investors, and auditors expect it. Some private companies use a simplified version called “GAAP for private companies” or opt for cash-basis reporting.
What does “rules-based” mean in the context of GAAP?
GAAP provides highly specific, detailed rules for most accounting situations — bright-line thresholds, specific criteria, and step-by-step guidance. This contrasts with IFRS, which sets broader principles and relies more on professional judgment. The trade-off: GAAP offers more consistency but less flexibility; IFRS offers more flexibility but more room for subjective interpretation.
What is the difference between GAAP and non-GAAP earnings?
GAAP earnings follow standard accounting rules. Non-GAAP (or “adjusted”) earnings exclude items management deems non-recurring or non-operational — such as restructuring charges, stock-based compensation, or amortization from acquisitions. Non-GAAP figures must be reconciled to GAAP in SEC filings.
Will the U.S. ever adopt IFRS?
Full convergence has been discussed for over two decades but hasn’t happened. The SEC explored adoption in the early 2010s but ultimately decided against requiring it. The two frameworks have been converging on specific standards (like revenue recognition and leases), but full adoption of IFRS in the U.S. remains unlikely in the near term.