You already know how to read an income statement and find the net income. But not all profits are created equal. The real skill is in assessing the quality of those earnings. High-quality earnings are sustainable and come from a company's core business operations. Low-quality earnings might be propped up by one-time events, accounting tricks, or unsustainable practices.

Professional analysts are like detectives, looking for clues that a company's reported profit doesn't tell the whole story. They scrutinize how a company recognizes its revenue. For example, is the company booking sales before the customer has fully committed or before the service is truly delivered? This is a classic red flag known as aggressive revenue recognition.

Another tactic to watch for is the capitalization of operating expenses. Instead of recording a cost as an immediate expense on the income statement, a company might classify it as an asset on the balance sheet. This pushes the expense into the future (as depreciation), making current profits look much better than they actually are. It's a way of borrowing profit from future periods.

Comparing the financial statements of two companies can be like comparing apples and oranges, especially if one is a giant and the other is a startup. A common-size statement solves this by converting all numbers into percentages.

For an income statement, every line item is shown as a percentage of total revenue. For a balance sheet, every item is a percentage of total assets. This removes the effect of size and lets you compare companies on an even playing field. You can see how efficiently a company manages its expenses relative to its sales, or how its asset structure compares to an industry benchmark.

Let's compare the cost structures of two fictional retail companies.

Company B is four times larger, but the common-size columns reveal a lot. Company A has much better gross margins (60% vs. 50%), but Company B is more efficient with its selling, general, and administrative (SG&A) expenses. This kind of insight is hidden when you only look at the raw dollar amounts.

Net income is an opinion; cash flow is a fact. Accounting earnings are subject to many estimates and non-cash expenses, like depreciation. Cash flow, on the other hand, tracks the actual money moving in and out of the business. For this reason, many analysts focus on Free Cash Flow (FCF) as the ultimate measure of a company's health.

FCF is the cash a company generates after accounting for the capital expenditures needed to maintain or expand its asset base. This is the cash left over for the company to repay debt, pay dividends, or buy back shares.

Amazon is a classic case study. For many years, the company reported very little net income. Critics claimed it wasn't profitable. But savvy investors looked at its massive and growing FCF. Amazon was reinvesting every dollar it could back into the business—building warehouses, developing technology, and expanding its reach. It chose to sacrifice short-term accounting profit to generate enormous long-term cash flows and shareholder value.

Global corporations aren't monolithic. They are often collections of different businesses or regional operations. Public companies are required to disclose segment reports, which break down their revenue and profits. This allows you to see which parts of the company are thriving and which are struggling.

To compare the performance of these different segments, analysts often use ratios like Return on Assets (ROA). ROA measures how efficiently a company is using its assets to generate earnings. A higher ROA is better.

For example, Mercedes-Benz Group can use ROA to evaluate the efficiency of its different segments. Is the Mercedes-Benz Cars division in North America generating a better return on its assets than the Mercedes-Benz Vans division in Europe? By analyzing performance at this granular level, both company management and external analysts can make much more informed decisions about capital allocation and strategy.

Now, let's test what you've learned about digging deeper into financial statements.

By moving beyond surface-level numbers and applying these analytical techniques, you can develop a much more nuanced and accurate picture of a company's true financial health.