How to Read an Income Statement
How much did a company sell over a year, and of that, how much did it really keep? The income statement answers this question 'from top to bottom.'
Read the Income Statement from Top to Bottom
The income statement shows how much a company earned and spent over a period (usually a quarter or a year). The key is the structure of 'being shaved down from top to bottom.'
Revenue ← at the top, the total of what was sold − Cost of goods sold = gross profit − Selling, general & administrative expenses = operating income − Interest expense and taxes = net income ← at the bottom
This is exactly why the revenue at the top is called the 'top line' and the net income at the bottom the 'bottom line.' Going down from the top, subtracting various costs one by one, you get the money that's truly left.
Distinguish These Three Profits
'Profit' appears several times in an income statement. To avoid confusion, just distinguish these three.
- Gross profit: revenue minus only the direct cost of making the product (cost of goods sold). The margin of the business itself. - Operating income: gross profit minus SG&A expenses like personnel and marketing costs. It's 'the money earned from the core business.' It's one of the numbers investors watch most importantly. - Net income: the final profit after subtracting even interest and taxes. It becomes the raw material for earnings per share (EPS).
If operating income is good but net income is bad, it can be a signal of a problem outside the core business (interest, one-off losses, etc.).
Don't be fooled by 'one-off profits.' Items that don't recur every year, like the profit from selling a building, can inflate net income. So to see the strength of the core business, you have to look at the flow of operating income together.
Don't Look at Just One Year—Look at the Trend
Looking at just one year of an income statement creates an illusion. It's important to lay out at least 3 to 5 years side by side and look at the 'trend.'
- Is revenue growing each year, or standing still? - Is the operating margin (operating income ÷ revenue) holding, or being shaved down? - Why did a number suddenly spike in a particular year?
Not a single table but 'the trend over several years' tells you the company's true ability.
よくある質問
Q. If revenue grows, is it unconditionally a good company?
Not necessarily. If revenue grows but the operating margin keeps falling, it could mean the company is selling too cheaply or its costs are rising fast. You have to look at revenue growth and profitability (margins) together for a balanced judgment.
Q. Are all loss-making companies bad?
You can't conclude that. Early-growth companies sometimes deliberately accept losses to invest heavily for the future. However, a loss also means greater risk, so you must always check why it's in the red (because of growth investment, or because the core business isn't working). This is not a recommendation but a starting point for judgment.
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