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Academy Level 5 · Making decisions · Lesson 17 of 20 · 5 min

Build a falsifiable stock thesis

Writing down what you believe, what would prove you wrong, and when you will check — before you buy.

The hardest part of investing is not finding ideas. It is remembering, eighteen months later, what you actually believed when you bought — and being honest about whether it happened. Memory is generous to itself. Writing is not.

A useful stock thesis states what the market may be missing, identifies the operating evidence that should close the gap, and defines what would prove the idea wrong. It is a testable decision record, not a prediction that the price will rise.

What to look at

The shape of it

Thesis = Variant view + Business driver + Evidence + Failure condition

An example

Example: recurring-revenue mix lifts operating margin faster than expected over the next four quarters.

Where people go wrong

“The stock looks cheap” is not a thesis unless you explain why earnings or cash-flow expectations are wrong.

A thesis you cannot falsify is not a thesis, it is a hope. The failure condition is the most valuable line in the whole document, and it is the one people most often leave out.

Check your understanding

1. Which line is the most important part of a thesis?

Show answer

The failure condition. It is what makes the thesis testable and tells you when to change your mind.

2. Is 'the stock looks cheap' a thesis?

Show answer

Only if you explain why expectations are wrong. Cheapness needs a reason the market is mispricing future earnings or cash flow.

Try it now

Pick one company and write a four-line thesis: variant view, business driver, evidence, failure condition.

Choose a stock to research →