Intermediate
5 min read

Building an Investment Thesis

A thesis states what you believe, why, and what would prove you wrong.

The four parts

A usable thesis fits on one page.

  • What the business does and how it makes money
  • Why you believe it can be durably stronger in five to ten years
  • What evidence supports that, and where the evidence is missing
  • What specific developments would tell you the thesis is wrong

Write the falsification condition first

Without a pre-written condition for being wrong, any decline becomes a buying opportunity and any rise becomes confirmation. The falsification condition is the part that makes the thesis honest.

Revisit on results, not on price

Review a thesis when the company reports, not when the price moves. Price movement is not evidence about the business.

Why this matters

A written thesis is the only way to know later whether you were right for the right reasons.

Terms used in this lesson

Falsification
The pre-written condition that would tell you your investment reasoning was wrong.
See the full glossary
Written by
Suggested Investments Research Team
Content type
Educational article
Published
2026-09-13
Last reviewed
2026-09-13

Sources and methodology

Educational content only. This lesson is not investment, tax or legal advice and does not recommend buying or selling any specific investment. All investing involves the risk of loss.