Depreciation

Depreciation is an accounting method that allocates the cost of a tangible fixed asset over its expected useful life. Rather than recognizing the full purchase price as an expense in year one, businesses spread this cost systematically — reducing reported income each year and reflecting the asset's declining value on the balance sheet. Common methods include straight-line (equal annual amounts), declining balance (larger amounts early), and units-of-production (based on actual usage).

For investors, depreciation matters in several key ways. First, it's a non-cash expense — it reduces taxable income without requiring an actual cash outflow, which means a company's cash flow can be higher than its reported net income. This is why analysts focus on EBITDA (Earnings Before Interest, Taxes, Depreciation, and Amortization) to assess operating cash generation. Second, capital-intensive industries like manufacturing, airlines, and utilities carry heavy depreciation loads that can depress reported earnings despite strong underlying economics. Third, comparing a company's capital expenditures (capex) to its depreciation gives insight into reinvestment needs — if capex consistently exceeds depreciation, the business may need significant ongoing investment just to maintain operations.

Depreciation also creates a tax shield: the higher the depreciation expense, the lower the taxable income. Accelerated depreciation methods (front-loading expenses) are particularly valuable to businesses because they defer taxes. Real estate investors use depreciation aggressively — rental property depreciation can offset rental income, creating phantom tax losses even when properties appreciate in value. Warren Buffett famously called depreciation "the most misunderstood item on the income statement" because it represents real economic costs (wear and tear, obsolescence) that will eventually require cash to replace.