Accounting Principles for Investors

Beginner

What Is Accounting, and Why Investors Care Beginner

Accounting is the system companies use to record, summarize, and report their financial activity. Public companies must publish standardized financial statements on a regular schedule, and those statements are the primary evidence investors use to judge whether a business is healthy, growing, and fairly priced. Every ratio in the Stock Market guide is ultimately built from numbers found in these statements.

✓ GAAP (Generally Accepted Accounting Principles): the standardized rulebook U.S. public companies follow when preparing financial statements.
✓ 10-K: a company's detailed annual report filed with the SEC. 10-Q: the quarterly version.
✓ Auditors: independent firms that review a company's statements for accuracy before they're published.

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The Three Core Financial Statements Beginner

Nearly everything in financial analysis flows from three documents. The Income Statement shows whether a company was profitable over a period of time. The Balance Sheet shows what the company owns and owes at a single point in time. The Cash Flow Statement shows how cash actually moved in and out of the business. Each tells a different part of the story — a company can look profitable on the income statement while its cash flow statement reveals real trouble, and vice versa.

✓ Income Statement (a.k.a. Profit & Loss / P&L): revenue, expenses, and profit over a period (e.g., a quarter or year).
✓ Balance Sheet: assets, liabilities, and equity as of a specific date — a financial 'snapshot'.
✓ Cash Flow Statement: actual cash generated or used, split into operating, investing, and financing activities.

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The Accounting Equation: Assets, Liabilities, Equity Beginner

Every balance sheet is built around one unbreakable equation. Assets are everything the company owns or is owed (cash, inventory, buildings, equipment, receivables). Liabilities are everything the company owes to others (loans, unpaid bills, bonds). Equity is what's left over for shareholders after subtracting what's owed from what's owned — it's the company's actual net worth on paper.

Formula

Assets = Liabilities + Shareholders' Equity

Example

A company with $80 million in assets and $30 million in liabilities has $50 million in shareholders' equity.

✓ Shareholders' equity is also called 'book value' — this is the number behind the P/B ratio from the Stock Market guide.
✓ This equation must always balance — it's why the statement is called the 'balance' sheet.

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Revenue, Expenses, and Net Income Beginner

Revenue (also called 'sales' or 'the top line') is the total money a company brings in from selling its products or services, before any costs are subtracted. Expenses are the costs of running the business. What's left after subtracting all expenses from revenue is Net Income — often called 'the bottom line' and the most commonly cited measure of a company's profit.

Formula

Net Income = Revenue − All Expenses (including taxes and interest)

✓ 'Top line' growth (revenue) and 'bottom line' growth (net income) don't always move together — watch both.
✓ Net income is the number used to calculate EPS and, from there, the P/E ratio.

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Accrual Accounting vs. Cash Accounting Beginner

Most public companies use accrual accounting, which records revenue when it's earned and expenses when they're incurred — regardless of when cash actually changes hands. Cash accounting, by contrast, only records transactions when cash is actually received or paid. Accrual accounting gives a more complete picture of ongoing business activity, but it's also why 'profit' and 'cash' can tell very different stories, which is exactly why the Cash Flow Statement exists as its own report.

Example

A company that ships $1 million of product in December but doesn't get paid until February still records that $1 million as December revenue under accrual accounting.

✓ Accrual accounting is required under GAAP for most public companies.
✓ This is precisely why a profitable company (on paper) can still run out of cash.

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Intermediate

Balance Sheet Detail: Current vs. Non-Current Intermediate

Balance sheet items are split by how quickly they convert to cash or come due. 'Current' items are expected to be settled within a year; 'non-current' (or 'long-term') items extend beyond a year. This split is the foundation for measuring short-term financial health.

✓ Current assets: cash, short-term investments, accounts receivable, inventory.
✓ Non-current assets: property, plant & equipment (PP&E), long-term investments, intangible assets, goodwill.
✓ Current liabilities: accounts payable, short-term debt, accrued expenses due within a year.
✓ Non-current liabilities: long-term debt, deferred tax liabilities, pension obligations.

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Income Statement Detail: Gross, Operating, and Net Margins Intermediate

The income statement peels back profitability in layers, and each layer answers a different question about the business.

Formula

Gross Profit = Revenue − Cost of Goods Sold (COGS)
Operating Income = Gross Profit − Operating Expenses (SG&A, R&D)
Net Income = Operating Income − Interest − Taxes (+/− other items)

✓ Gross margin (Gross Profit ÷ Revenue): how efficiently the company produces what it sells, before overhead.
✓ Operating margin (Operating Income ÷ Revenue): profitability from core business operations, before financing costs and taxes.
✓ Net margin (Net Income ÷ Revenue): the bottom-line profitability after everything, including interest and taxes.
✓ Comparing these three margins over time reveals whether cost pressure is coming from production, overhead, or financing/taxes.

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EBIT and EBITDA Intermediate

EBIT and EBITDA strip out certain costs to make it easier to compare the core operating performance of companies with different debt levels, tax rates, or asset bases. They are not official GAAP measures, but they are extremely widely used by analysts.

Formula

EBIT (Earnings Before Interest & Taxes) = Net Income + Interest + Taxes
EBITDA = EBIT + Depreciation + Amortization

✓ EBITDA is often used as a rough proxy for operating cash generation, though it ignores capital expenditures.
✓ Because it excludes real costs (debt interest, taxes, and wear-and-tear on assets), EBITDA can make a heavily indebted or capital-intensive company look healthier than it is — always pair it with debt and cash flow figures.

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The Cash Flow Statement: Three Activities Intermediate

The cash flow statement splits all cash movement into three buckets, which together explain exactly why the company's cash balance changed from the start to the end of the period.

✓ Operating activities: cash generated (or used) by core business operations — usually the most important figure for judging business health.
✓ Investing activities: cash spent on or received from long-term investments, like buying equipment (capital expenditures) or acquiring other companies.
✓ Financing activities: cash flows from debt, equity, dividends, and stock buybacks — how the company funds itself and returns money to investors.
✓ A healthy, mature company typically shows positive operating cash flow, negative investing cash flow (it's investing in growth), and variable financing cash flow.

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Depreciation & Amortization Intermediate

Depreciation spreads the cost of a physical asset (like machinery or a building) over its useful life instead of expensing the entire cost the moment it's purchased. Amortization does the same thing for intangible assets, like patents or acquired trademarks. Both are non-cash expenses — they reduce reported profit without any cash actually leaving the company in that period, which is exactly why they get added back when calculating EBITDA and free cash flow.

Example

A company buys a $1 million machine expected to last 10 years. Instead of recording a $1 million expense immediately, it might record $100,000 of depreciation expense each year.

✓ Non-cash expense: reduces net income on paper but doesn't consume cash in the period it's recorded.
✓ The actual cash was already spent (or will be) when the asset was purchased — tracked in investing activities on the cash flow statement.

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Working Capital Intermediate

Working capital measures the cash a company has tied up in its day-to-day operating cycle — the buffer available to cover short-term obligations. It's a core measure of short-term financial flexibility.

Formula

Working Capital = Current Assets − Current Liabilities

✓ Positive working capital means a company can comfortably cover its near-term obligations.
✓ Negative working capital isn't always bad — some business models (like retailers that sell inventory before paying suppliers) can run efficiently with low or negative working capital.

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Liquidity Ratios: Current Ratio & Quick Ratio Intermediate

Liquidity ratios test whether a company can pay its short-term bills using its short-term assets. They're an early-warning system for financial distress.

Formula

Current Ratio = Current Assets ÷ Current Liabilities
Quick Ratio = (Current Assets − Inventory) ÷ Current Liabilities

Example

A company with $5 million in current assets and $2.5 million in current liabilities has a current ratio of 2.0.

✓ A current ratio below 1.0 means current liabilities exceed current assets — a potential red flag.
✓ The quick ratio ('acid-test ratio') is stricter, excluding inventory since it isn't always quickly convertible to cash.

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Leverage Ratios: Debt Levels & Interest Coverage Intermediate

Beyond the debt-to-equity ratio covered in the Stock Market guide, analysts check whether a company generates enough operating profit to comfortably cover its interest payments — a direct test of debt sustainability.

Formula

Interest Coverage Ratio = EBIT ÷ Interest Expense

Example

A company with $40 million in EBIT and $8 million in annual interest expense has an interest coverage ratio of 5.0x.

✓ A higher ratio means more of a cushion — the company earns several times its interest obligation.
✓ A ratio below roughly 1.5x is often viewed as a warning sign of financial distress risk.

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Advanced

Profitability Ratios: ROA, ROE, and ROIC Advanced

These three ratios each measure profit against a different base, and together they reveal how efficiently a company turns resources into profit.

Formula

ROA (Return on Assets) = Net Income ÷ Total Assets
ROE (Return on Equity) = Net Income ÷ Shareholders' Equity
ROIC (Return on Invested Capital) = Net Operating Profit After Tax ÷ (Debt + Equity)

✓ ROA shows how well the company uses everything it owns (regardless of how it was financed) to generate profit.
✓ ROE shows the return specifically to shareholders, and can be inflated by high debt (see DuPont analysis below).
✓ ROIC strips out the effect of the capital structure entirely, making it one of the cleanest measures of true business quality — many long-term investors treat it as a favorite metric.

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DuPont Analysis: Decomposing ROE Advanced

DuPont analysis breaks ROE into three components, revealing WHY a company's ROE is high or low — whether it comes from strong profit margins, efficient use of assets, or simply heavy financial leverage (debt).

Formula

ROE = Net Profit Margin × Asset Turnover × Equity Multiplier
(Net Income ÷ Revenue) × (Revenue ÷ Total Assets) × (Total Assets ÷ Equity)

✓ Net Profit Margin: profitability on each sales dollar.
✓ Asset Turnover: how efficiently assets are used to generate revenue.
✓ Equity Multiplier: how much leverage (debt) is amplifying returns to equity holders.
✓ Two companies can have identical ROE for very different reasons — DuPont analysis reveals whether that ROE is high-quality (from margins/efficiency) or risky (from leverage).

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Revenue Recognition Principles Advanced

Revenue recognition rules govern exactly WHEN a company is allowed to record revenue — a surprisingly complex area that's been at the center of many accounting scandals. Under modern GAAP standards (ASC 606), revenue is recognized when a company satisfies its performance obligation (e.g., delivers a product or completes a service), not necessarily when cash is collected.

✓ Multi-year contracts and subscriptions often recognize revenue gradually over the service period, not all at once.
✓ Aggressive or premature revenue recognition is one of the most common forms of earnings manipulation — a key reason to also check the cash flow statement, which is harder to manipulate.

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GAAP vs. Non-GAAP ('Adjusted') Earnings Advanced

Companies often report 'adjusted' or 'non-GAAP' earnings alongside official GAAP figures, excluding items management considers one-time or non-representative (like restructuring charges or stock-based compensation). These can offer useful insight into core, ongoing performance — but they're also unaudited and chosen by the company itself, so they can be used to present a rosier picture than GAAP numbers would show.

✓ Always check what's being excluded and whether those 'one-time' items keep recurring every single quarter.
✓ Stock-based compensation is a frequent adjustment — it's a real cost to shareholders (via dilution) even though it isn't a cash expense.
✓ When GAAP and non-GAAP earnings diverge significantly and persistently, treat it as a signal to dig deeper, not a footnote to ignore.

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Footnotes, Goodwill, and Off-Balance-Sheet Items Advanced

Some of the most important information in a financial filing lives outside the main statements. Footnotes disclose accounting policy choices, contingent liabilities (like pending lawsuits), and details behind the headline numbers. Goodwill — the premium paid in an acquisition above the target's identifiable net assets — sits on the balance sheet as an asset but isn't a physical or easily-valued one, and can be written down suddenly if an acquisition underperforms.

✓ Goodwill impairment: a write-down of goodwill's value, typically signaling that a past acquisition was overpriced or underperformed expectations.
✓ Contingent liabilities: potential future obligations (like lawsuits) disclosed in footnotes rather than fully reflected in the reported numbers.
✓ Operating leases, guarantees, and joint ventures can create obligations that don't fully appear on the balance sheet itself.

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Red Flags: Signs of Earnings Quality Problems Advanced

Experienced analysts cross-check the three statements against each other looking for inconsistencies, since these are some of the most common early warning signs of accounting trouble.

✓ Net income growing while operating cash flow stalls or declines — profit isn't converting to cash.
✓ Receivables growing much faster than revenue — a possible sign customers aren't actually paying (or revenue is being recognized too aggressively).
✓ Inventory building up faster than sales growth — could mean weakening demand.
✓ Frequent 'one-time' charges that recur every year — suggests non-GAAP adjustments are hiding a recurring, real cost.
✓ Sudden changes in accounting policies, auditors, or CFOs without clear explanation.

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Connecting Accounting Back to Stock Analysis Advanced

Every valuation ratio from the Stock Market guide is only as reliable as the accounting numbers feeding it. A low P/E built on inflated, low-quality earnings isn't actually a bargain. Strong ROE built on excessive debt isn't the same as strong ROE built on genuine efficiency. The real skill of investment analysis is combining both guides: use accounting principles to judge whether the underlying numbers are trustworthy, then use market/valuation ratios to judge whether the price being asked for those numbers is reasonable.

✓ Good analysis reads the financial statements first, and treats stock ratios as a second layer built on top of them.
✓ When something looks 'too good' in a ratio (unusually low P/E, unusually high ROE or margin), the accounting statements are exactly where you go to find out why.

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