Reading an income statement like an owner

An income statement tells you how much a business earned over a period, usually a quarter or a year. In Australia it is often called the profit and loss statement, or simply the P&L. Most people read it from the bottom: what was the profit? An owner reads it from the top, because each line answers a different question about how the business works.

The approach below follows the structure used in Warren Buffett and the Interpretation of Financial Statements by Mary Buffett and David Clark. The emphasis throughout is not on a single year’s figures but on how they behave over time, and on what they reveal about whether a business has a lasting advantage. Along the way, we will work through a simple illustrative example and note how the same reading applies to a small business’s own accounts.

The shape of an income statement

Every income statement follows roughly the same order, from revenue at the top to net profit at the bottom:

1. Revenue (sales)
2. minus cost of goods sold = gross profit
3. minus operating expenses (overheads, research, depreciation) = operating profit
4. minus interest, plus or minus one-off items = profit before tax
5. minus tax = net profit (net earnings)

Each subtraction removes a different kind of cost. Reading the statement well means asking, at each step, what that cost says about the business.

A worked example

Here is a simplified, hypothetical income statement for a company we will call Company A, alongside a competitor, Company B. The figures are illustrations only.

Both companies have the same revenue. Both report a profit. Yet they are completely different businesses, and the income statement shows why at almost every line.

Revenue: the starting point, not the conclusion

Revenue is the money coming in from sales. On its own it says very little. A business can grow revenue impressively while losing money on every sale. Revenue matters mainly as the denominator for everything that follows, and as a signal of demand when viewed over time.

Useful questions:

• Is revenue growing steadily, or lurching between good and bad years?
• Is growth coming from more customers, higher prices, or acquisitions?
• Does a large share depend on a few customers?

Revenue is recorded when earned, not when paid

Accounting rules generally record revenue when it is earned (when goods are delivered or services performed), not when the customer pays. That means revenue on the income statement can include sales that have not yet turned into cash. A business offering generous payment terms can show strong revenue while its bank balance struggles. This is one reason the cash flow statement, covered later in this series, is an essential companion to the income statement.

Cost of goods sold and gross profit: the first real test

Subtract the direct cost of making or buying what you sell, and you get gross profit. Divide it by revenue and you have the gross margin.

In the example, Company A’s gross margin is 60% and Company B’s is 20%. That single difference shapes everything below it.

This is the first place a competitive advantage shows itself. A business that can charge well above its direct costs, consistently, has something customers value or something competitors cannot easily copy. A business whose gross margin is thin, or swings wildly, is usually fighting on price. The book suggests that consistent gross margins of around 40% or more often indicate some form of durable advantage, while consistent margins below about 20% usually signal intense competition. Gross margin gets its own article in this series.

Operating expenses: what it costs to run the business

Below gross profit sit the costs of running the business:

• Selling, general and administrative expenses (SG&A): salaries, rent, marketing, sales, office costs.
• Research and development (R&D): the cost of creating new products.
• Depreciation: the gradual using-up of equipment and buildings.

The useful habit is to measure each against gross profit, not revenue. The question becomes: of every dollar of gross profit, how much is consumed just to keep the business running?

In the example:

Company A keeps most of what it earns. Company B spends more than all of its gross profit before interest, which is why its operating profit is negative. A business like Company A has room to absorb bad years; a business like Company B is always one problem away from a loss. These lines get detailed treatment in the articles on overheads and on depreciation.

Operating profit: what the business itself earns

Gross profit minus operating expenses gives operating profit, often called EBIT (earnings before interest and tax). It is the cleanest view of whether the business model itself works, before financing decisions and tax.

You will also see EBITDA (earnings before interest, tax, depreciation and amortisation) in many reports. It can be useful for comparisons, but treat it with care. Excluding depreciation makes capital-heavy businesses look more profitable than they are, because machines and buildings genuinely wear out and must be replaced. The book is firm that depreciation is a real cost.

Interest: the cost of borrowed money

Interest expense is the price of debt. It says less about the product than about the balance sheet. A business with a durable advantage rarely needs to borrow heavily, so its interest bill tends to be small relative to operating profit; the book suggests under about 15%. Company A pays interest equal to about 6% of operating profit. Company B’s interest is larger than its operating profit, which means it cannot cover its borrowing costs from its core business at all.

The article “Debt as a warning light” explores this in depth.

One-off items: read them, then set them aside

Gains or losses from selling assets, write-downs, restructuring costs and other unusual items can make one year look much better or worse than the underlying business.

Company B is the classic case. Without the $5 million gain from selling property, it would have reported a pre-tax loss of $4 million. The headline profit hides an unprofitable business that is selling assets to stay afloat.

The book’s advice is simple: note one-off items, then look past them. A business is valued on what it earns repeatedly, not on what it earned once.

A note on “underlying” profit

Many Australian listed companies report both a statutory profit (calculated under accounting standards) and an underlying or “normalised” profit that excludes items management considers unusual. Underlying figures can be helpful, but they are chosen by management. It is worth reading what has been excluded and asking whether those items really are unusual. If “one-off” restructuring costs appear every year, they are part of the business.

Tax

Tax reduces profit to the bottom line. The Australian corporate tax rate is generally 30%, with a lower rate for many smaller companies that meet the relevant tests. Unusually low tax in a particular year may reflect losses carried forward, tax concessions or timing differences. These can be legitimate, but they rarely repeat indefinitely.

Net earnings: the bottom line, read over many years

After interest, one-off items and tax, you arrive at net earnings or net profit. Two measures are worth tracking:

• Net earnings as a share of revenue (net margin). The book suggests that businesses consistently converting a large share of revenue into net profit, roughly 20% or more, often have an advantage, while those consistently under 10% are usually in fiercely competitive industries. Company A’s net margin is about 24%; Company B’s is about 1.4%, and that only because of the property sale. Treat these bands as rules of thumb, not laws.
• The trend over ten years. One great year proves little. A steady upward line, through good economies and bad, proves a lot.

Earnings per share

For companies with shareholders, net earnings divided by the number of shares gives earnings per share (EPS). The book highlights consistent, rising EPS as one of the clearest signals of a durable business. Watch for EPS that rises only because the share count is shrinking through buybacks, or falls because new shares have been issued. Both are covered in the article on buybacks.

Reading ten years, not one

The single most important habit the book recommends is to lay out many years of income statements side by side. A useful table for any business:

Patterns that suggest a durable business: stable or rising margins, stable cost ratios, small interest costs and steadily rising earnings. Patterns that suggest a struggling one: volatile margins, rising cost ratios, heavy interest and earnings that swing between profit and loss.

Applying this to your own business

The same reading works for a small business’s own P&L, prepared by your bookkeeper or accountant. A few adaptations:

• Use monthly and annual figures. Monthly figures show seasonality; annual ones show trends.
• Track gross margin by product or service where possible. Averages hide which offerings actually make money.
• Watch overheads as a share of gross profit. Overheads tend to creep up during good times and become hard to cut later.
• Separate one-off items so you can see the real trend.
• Compare with your own history before comparing with others. Your own trend is the most reliable benchmark.

For a founder, the five questions below describe the income statement worth designing for from the beginning.

Where to find income statements

For listed Australian companies, income statements appear in annual and half-year reports, published on company investor pages and through the ASX announcements platform. The full financial statements, with notes, are more reliable than summary presentations, which tend to emphasise the most favourable measures. The notes often explain one-off items, segment results and accounting choices that the headline figures hide.

For private businesses, including your own, the income statement comes from your accounting system or accountant. Ask for comparative figures (this year against last year, and this month against the same month last year) so trends are visible without extra work.

Five questions to ask of any income statement

1. Is the gross margin high and stable?
2. How much of gross profit do overheads, research and depreciation consume?
3. Is interest small relative to operating profit?
4. Are the profits clean, or flattered by one-off items?
5. Are net earnings rising consistently over many years?

Common mistakes

Reading only the bottom line. Net profit hides how it was produced.

Comparing across very different industries. A software company and a supermarket have naturally different margins. Compare like with like.

Trusting one year. Consistency over time is the signal.

Ignoring depreciation. EBITDA-style figures can flatter capital-heavy businesses.

Accepting “underlying” profit without reading the adjustments.

Bringing it together

An income statement is a story told from top to bottom. Gross margin shows pricing power. Operating expenses show what it costs to stay in business. Interest shows dependence on lenders. One-off items show what will not repeat. Net earnings, read over many years, show whether the whole story adds up to a durable business.

Reading it like an owner means asking, at every line, what that number reveals about the business’s ability to keep earning, not just what it earned last year.

Source: Mary Buffett and David Clark, Warren Buffett and the Interpretation of Financial Statements (2008). Company A and Company B are hypothetical illustrations. Tax rates are summarised generally; check current rules with an adviser. This article is general information, not financial or investment advice.