Learn how income statements, margins, EPS, P/S and P/E ratios help assess profitability, earnings quality, and company valuation.
What Is an Income Statement?
An income statement, also commonly called a profit and loss statement or statement of earnings, is a financial statement that measures a company’s financial performance over a specific accounting period. It records how much revenue a company generated, how much cost and expense it incurred, and whether it ultimately produced a profit or loss during a quarter, half-year, or full year. Unlike the balance sheet, the income statement is not a point-in-time statement, but a period statement.
The core logic of the income statement can be summarized as: profit = revenue - expenses. Revenue usually comes from selling goods, providing services, or other core business activities. Expenses include cost of sales, operating expenses, interest expense, income tax, and certain special items. If a company’s revenue cannot cover its costs and expenses over the long term, its business model, cost control, or market demand requires further review.
The value of the income statement lies not only in showing the amount of net profit, but also in revealing how that profit is formed. By examining revenue growth, cost of sales, gross profit, selling and administrative expenses, operating profit, interest expense, and taxes, analysts can observe whether profitability comes from price increases, volume growth, cost reductions, expense control, or one-off items.
Basic Structure of the Income Statement
Revenue: the inflow of economic benefits obtained by the company from selling goods or providing services, and the starting point of profit formation.
Cost: expenses directly related to goods sold or services provided, such as raw materials, direct labor, and manufacturing overhead.
Expenses: expenditures incurred by the company in maintaining operations, sales, administration, research and development, financing, and tax payments.
Profit: the result after deducting costs and expenses from revenue, which may be a profit or a loss.
How Revenue and Cost of Goods Sold Affect Gross Profit
Revenue refers to the economic benefits a company obtains from its normal operating activities. Under different business models, revenue sources may vary significantly. Retail companies usually generate revenue from merchandise sales, software companies may generate revenue from subscription services, platform companies may generate revenue from commissions or advertising, and manufacturers may generate revenue from product delivery and long-term contracts.
Cost of Goods Sold (COGS) refers to the direct costs incurred by a company to produce or acquire the products that have been sold. For manufacturers, COGS usually includes raw materials, direct labor, and manufacturing overhead. For retailers, COGS usually includes the cost of purchased merchandise. Service companies may use terms such as cost of services or cost of revenue.
Gross profit is the result after deducting cost of goods sold from revenue. The gross margin is calculated as: gross margin = gross profit ÷ revenue × 100%. If a company has revenue of RMB 10 billion and cost of goods sold of RMB 6 billion, its gross profit is RMB 4 billion and its gross margin is 40%. Gross margin is used to observe a company’s product pricing power, cost control capability, and changes in product mix.
What to Focus on When Analyzing Revenue Quality
Sources of revenue growth: whether growth comes from higher sales volume, price increases, new products, acquisitions, exchange rate changes, or one-off items.
Revenue sustainability: subscription revenue, long-term contract revenue, and repeat purchase revenue are usually easier to forecast than one-off projects.
Customer concentration: if the top five customers account for a high proportion of revenue, the company may face bargaining power and customer loss risks.
Revenue recognition basis: long-term contracts, platform businesses, and multiple-element sales arrangements may involve more complex revenue recognition rules.
Revenue growth does not automatically mean profitability has improved. If cost of goods sold, customer acquisition costs, logistics costs, or after-sales costs rise faster than revenue, gross profit and net profit may be compressed. Therefore, income statement analysis should examine both revenue scale and revenue quality.
What Do Operating Expenses and Operating Profit Indicate?
Selling, General and Administrative Expenses (SG&A) are expenses incurred by a company to sell products, manage the organization, and maintain daily operations. They usually include sales staff compensation, marketing, office expenses, management compensation, professional service fees, and some lease expenses.
Research and Development (R&D) expenses are common in technology, pharmaceutical, manufacturing, and software companies, and are used for product development, technology improvement, and experimental research. Rising R&D expenses are not necessarily negative, but analysts need to assess whether the investment is related to future products, patents, revenue growth, or competitive advantages.
Operating profit is the result after deducting cost of goods sold and operating expenses from revenue, and is commonly used to measure the profitability of a company’s core operating activities. Earnings Before Interest and Taxes (EBIT) is often used to compare operating performance across different capital structures and tax environments, but reporting presentation may differ among companies.
Common Methods for Analyzing Operating Expenses
First calculate the gross margin to determine whether the product or service itself has sufficient profit space.
Then calculate SG&A as a percentage of revenue to observe whether sales and administrative expenses are diluted as revenue grows.
Check R&D as a percentage of revenue to determine whether R&D investment matches the company’s industry stage and strategy.
Calculate the operating margin, meaning operating profit ÷ revenue × 100%.
Observe the 3- to 5-year trend to avoid judging management efficiency based on expense fluctuations in a single year.
Compare with peer companies to confirm whether differences in expense ratios are caused by business model differences.
A decline in the expense ratio may indicate improved management efficiency, but it may also mean the company has cut necessary investments such as R&D, brand building, or customer service. A rise in the expense ratio may indicate increased expansion investment, or it may indicate declining operating efficiency. Analysis should be verified together with management commentary, the business stage, and the cash flow statement.
| Item Name | Key Parameters | Applicable Scenario | Main Risk |
|---|---|---|---|
| Revenue and Gross Profit | Revenue growth rate, COGS, gross profit, gross margin; observation period is usually 4 to 12 quarters | Assessing product pricing power, cost control, and revenue quality | Revenue growth may come from one-off projects, while gross margin may also be affected by product mix and accounting presentation |
| Operating Expenses and Operating Profit | SG&A as a percentage of revenue, R&D as a percentage of revenue, operating margin, EBIT | Analyzing management efficiency, operating leverage, and core business profitability | Excessive expense cuts may weaken long-term competitiveness, while expense expansion may also drag on short-term profit |
| Interest and Taxes | Interest expense, income before tax, effective tax rate, interest coverage ratio | Observing debt costs, tax impact, and capital structure pressure | High debt may compress profit when interest rates rise, and tax rate changes may also affect comparability |
| Net Profit and Valuation Metrics | Net margin, earnings per share, price-to-sales ratio, price-to-earnings ratio; should be combined with cash flow and peer comparison | Integrating profitability results with market valuation levels | Net profit may be affected by one-off items, and valuation metrics should not be used alone as a basis for trading decisions |
How Interest, Taxes, and Special Items Affect Net Profit
Interest expense reflects the cost a company bears for using debt financing. The larger the debt scale and the higher the interest rate, the higher interest expense usually becomes. For highly leveraged companies, even if operating profit remains stable, rising interest expense may compress income before tax and net profit.
Income before tax is the profit formed before deducting income tax. Income tax is the tax expense estimated or recognized by the company based on applicable tax rates and tax rules. The effective tax rate is usually calculated as income tax expense divided by income before tax. If the effective tax rate deviates significantly from historical levels or peer levels, analysts need to check one-off tax adjustments, loss carryforwards, regional revenue mix, and tax law changes.
Net profit is the final result after deducting cost of goods sold, operating expenses, interest, taxes, and other items from revenue. Earnings Per Share (EPS) is usually calculated as net profit attributable to ordinary shareholders divided by the weighted average number of ordinary shares. If the company has potentially dilutive instruments such as options or convertible bonds, diluted EPS also needs attention.
Why Special Items Need to Be Identified Separately
Restructuring expenses: may arise from layoffs, store closures, business integration, or organizational adjustments.
Asset impairment: may indicate that the carrying value of goodwill, fixed assets, inventory, or intangible assets needs to be reduced.
Discontinued operations: may come from selling or closing a business line and need to be distinguished from continuing operations.
Litigation and regulatory fines: may affect short-term profit and may also reflect governance or compliance risk.
One-off gains: such as gains from asset sales or investment income, may increase current-period net profit but are not necessarily sustainable.
The key issue with special items is not their name, but whether they are repeatable, whether they are related to core operations, and whether they will affect future cash flow. If a company repeatedly reports so-called one-off expenses over a long period, analysts should treat them as recurring risks in the business model or management efficiency rather than fully excluding them.
How to Combine the Income Statement with Other Statements
The income statement explains whether the company is profitable, the balance sheet explains what assets and funding structure support operations, and the cash flow statement explains whether profit can be converted into cash. The three financial statements are connected, and reading any one of them in isolation may lead to a one-sided judgment.
For example, rapid revenue growth should be explained through accounts receivable, inventory, and operating cash flow. If revenue growth is accompanied by a rapid increase in accounts receivable while operating cash flow does not improve correspondingly, collection quality may require further review. Similarly, if net profit growth mainly comes from asset sales while operating profit from the core business has not improved, earnings sustainability needs to be reassessed.
Analytical Process for Integrating the Three Financial Statements
First read the income statement and identify trends in revenue, gross profit, operating profit, and net profit.
Then read the balance sheet and check whether accounts receivable, inventory, debt, and shareholders’ equity support profit changes.
Next, read the cash flow statement and compare whether operating cash flow matches net profit.
Identify one-off items and distinguish profit from continuing operations from non-recurring gains and losses.
Calculate key ratios and compare them with the past 3 to 5 years and peer companies in the same industry.
Combine the business model, competitive advantages, management quality, and industry environment to form a conditional judgment.
The goal of integrated analysis is not to find a single perfect indicator, but to build an evidence chain. If revenue growth, gross margin improvement, stronger operating cash flow, controllable debt, and a supportive industry environment are aligned, the consistency of fundamental evidence is relatively high. If profit growth does not match cash flow, asset quality, or management explanations, greater uncertainty should be retained.
How to Understand the Relationship Among P/S Ratio, Market Capitalization, and Share Price
Market capitalization is the total value assigned by the market to all of a company’s issued ordinary shares. A common calculation is: market capitalization = current share price × number of issued shares. Share price can also be understood in reverse as market capitalization divided by the number of issued shares. Share repurchases, additional share issuance, and stock splits all affect the number of shares, but do not necessarily change the company’s actual operating capability.
The Price-to-Sales Ratio (P/S) is usually calculated as a company’s market capitalization divided by revenue over the latest 12 months, or as share price divided by revenue per share. This metric is often used for companies with relatively stable revenue but volatile profit, or for comparing companies with similar business models within the same industry.
The Price-to-Earnings Ratio (P/E) is usually calculated as share price divided by earnings per share, or as market capitalization divided by net profit. P/E is highly affected by net profit. If net profit fluctuates significantly due to one-off items, this metric may become distorted. Enterprise Value (EV) related metrics further consider debt and cash, making them suitable for comparing companies with significantly different capital structures.
Points to Note When Using Valuation Metrics
P/S does not reflect profit margin. A company with a low P/S ratio may still incur long-term losses or face high debt pressure.
P/E is sensitive to net profit. If net profit is affected by impairment, asset sales, or tax adjustments, comparability will decline.
EPS may be affected by share repurchases. Higher EPS does not necessarily mean the profitability of the core business has improved.
Valuation ranges differ significantly across industries. Banks, software companies, retailers, utilities, and cyclical industries should not be directly compared horizontally.
Valuation metrics should be used together with growth rate, profit margin, cash flow, debt level, and industry cycle.
How to Form an Objective Company Analysis Conclusion
After completing fundamental analysis, analysts need to place quantitative data and qualitative information within the same framework. Quantitative data include revenue, profit, cash flow, assets, liabilities, and valuation metrics. Qualitative information includes the business model, competitive advantages, management quality, corporate governance, industry landscape, and regulatory environment.
This stage is not an exact science, because future revenue, profit margins, costs, interest rates, and industry demand all involve uncertainty. A more reasonable approach is to write conclusions in conditional terms: if revenue growth continues, gross margin remains stable, expense ratios are controllable, cash flow matches profit, and industry demand does not deteriorate significantly, the company’s earnings quality may be easier to verify. If several of these conditions change, the original judgment needs to be reviewed.
Checklist for Reducing Bias
Do not directly infer that a company’s stock is higher quality simply because you personally like the brand.
Do not select only the data that support your existing view; also record contrary evidence and uncertain factors.
Do not equate short-term price movements with an improvement or deterioration in fundamentals.
Do not use a single indicator to determine the analytical conclusion; profitability, cash flow, the balance sheet, and valuation should all be checked.
Do not ignore differences in trading horizons, as short-term trading and long-term holding focus on different risk variables.
Behavioral financeresearch shows that investors’ and traders’ judgments may be affected by confirmation bias, anchoring, overconfidence, and loss aversion. TheProspect Theoryproposed by Daniel Kahneman and Amos Tversky in 1979 shows that people are not always fully rational when facing gains and losses. Therefore, fundamental analysis requires not only data, but also the recording of assumptions, contrary evidence, and invalidation conditions.
Knowledge Boundaries for Choosing Trading Methods Based on Analysis Results
After completing company research, the next step for analysts is usually to clarify the observation method rather than directly arriving at a single trading action. Trading direction, holding period, and tool selection should match the analytical assumptions, risk tolerance, and market environment. Going long, short selling, short-term trading, and long-term holding all correspond to different risk structures.
Going long means holding stocks or related instruments based on a price-rising scenario. Short selling means establishing an opposite-direction position based on a price-declining scenario. Short-term trading focuses more on events, valuation repair, price reaction, and liquidity. Long-term holding focuses more on earnings compounding, cash flow, dividend policy, and the sustainability of competitive advantages. The two should not be mixed casually.
If the analytical focus is valuation repair after a short-term one-off shock, the nature of the event, market reaction, liquidity, and subsequent disclosures need to be closely observed.
If the analytical focus is long-term earnings growth, revenue quality, gross margin, cash flow, capital expenditure, and competitive advantages need to be closely observed.
If the analysis involves a short-selling scenario, additional attention needs to be paid to upside price risk, securities borrowing costs, forced liquidation, and regulatory restrictions.
If the analysis involves derivative instruments, leverage, margin, spreads, overnight fees, and contract expiry rules need to be checked.
The ultimate purpose of fundamental analysis is to help traders understand company value, earnings quality, and sources of risk, rather than to promise a particular price path. The income statement provides clues about profitability, the balance sheet provides clues about financial structure, and the cash flow statement provides clues about funding quality. Comparing this evidence with market price forms a more complete stock research process.
Questions Related to Income Statements and Valuation Analysis
What Is the Difference Between an Income Statement and a Cash Flow Statement?
The income statement records a company’s revenue, costs, expenses, and profit over a certain period, reflecting accounting profitability. The cash flow statement records cash inflows and outflows, reflecting actual changes in funds. A company may have profit but weak cash flow, so the two statements need to be analyzed together.
What Is the Difference Between Gross Profit and Net Profit?
Gross profit is the result after deducting cost of goods sold from revenue, mainly reflecting the profit space of the product or service itself. Net profit is the final profit after further deducting operating expenses, interest, taxes, and other items, reflecting a more complete profitability result.
Why Is Operating Profit Often Used to Observe Core Operating Capability?
Operating profit excludes some financing and tax factors and is closer to the company’s ability to generate profit from its core business. It can help analysts observe the relationship among revenue, costs, and operating expenses, but it still needs to be verified together with cash flow and the balance sheet.
In What Scenarios Is the Price-to-Sales Ratio Useful?
The price-to-sales ratio is commonly used to compare companies in the same industry with similar business models and comparable revenue presentation, especially when net profit fluctuates significantly. However, it does not reflect profit margins, debt, or cash flow quality and should not be used alone.
Why Should the Three Financial Statements Be Read Together?
The income statement explains profitability results, the balance sheet explains assets and funding structure, and the cash flow statement explains cash changes. The three are interconnected, and only by reading them together can analysts more fully judge revenue quality, earnings sustainability, debt repayment pressure, and cash-generating ability.
