What can ratios never tell you?

It would be a strange course that spent sixteen lessons on ratios without admitting their limits. Ratios are powerful precisely because they compress — and compression always throws information away. Knowing what they can't see is as professional as knowing what they can.

Ratios look backward

Every ratio in this course is built from past financial statements — history, sometimes months old by the time it's published. They describe where a company has been, not where it's going. A superb five-year trend can reverse the day a key patent expires or a competitor launches something better. Ratios are the rear-view mirror: essential, but not the windshield.

Ratios miss the things that don't fit on a statement

A company's most valuable assets are often invisible to the balance sheet:

• Brand and reputation — trust that took decades to build and that no line item captures.
• Management quality — the judgement and integrity of the people running the business.
• Competitive moat — network effects, patents, switching costs that protect future profits.
• Culture and talent — the people who actually make the product.
• Industry disruption on the horizon — a technology or regulation that could reshape everything, invisible until it arrives.

None of these appear in a ratio, yet any of them can matter more than every number combined.

Ratios can be technically true and still mislead

As earlier lessons showed, honest accounting choices, one-off events, and industry differences can all make a correct ratio point the wrong way. And a ratio can be right about the past and useless about the future — a shrinking company can post beautiful margins right up until it disappears.

So what are ratios for?

They are for asking better questions, not delivering final answers. A weak ratio tells you where to look, not what to conclude. Ratios narrow a vast, messy company down to a handful of sharp questions — and then the real work of judgement begins, combining the numbers with everything the numbers can't see. Used that way, they're indispensable. Mistaken for the whole truth, they're a trap.

Try it now

Pick a company you actually know as a customer, and start by writing down two things you know about it — its brand, a new product, a management change — before you look at any number.

Then look. Here is the ratio side, for one company:

1. Read what those ratios say. Then read the same ratios for your own company; the link opens Coca-Cola, and you change the symbol to the company you picked:

Open KO.US — fundamentals in the EODHD Terminal

2. Go looking for your two written-down items in the company profile. Apple's is below, prose included:

Confirm what you already suspect: there is no line for management quality, none for a moat, none for a product about to launch. The nearest thing is a prose description, and prose is not a ratio. Your own company's profile, on the same Terminal page, reads the same way. 3. Sit with the gap between the two lists. Every ratio in this course was built from the financial statements, and everything you wrote down first was not. That gap is exactly why ratios inform judgement rather than replace it.