Tutorial: write an investment thesis

Not what the company does. Why it earns more than it costs to run, and why that will continue. If this sentence needs a paragraph, you do not understand the business yet.

Markets are mostly efficient, so if you think you have found a bargain, your first question should be: why has nobody else? There must be an answer. Perhaps it is too small for institutions, or the good news is two years out, or the market is extrapolating a temporary problem. If there is no answer, there is probably no bargain.

This is the part everyone skips, and it is the only part that will save you money. Name the three specific developments that would mean the thesis is broken. Margin falls below X. The moat source disappears. The debt cannot be refinanced.

Do not edit it as events unfold. The whole value of the document is that it records what you thought before you knew, which is the only honest measure of whether you are any good at this.