The scope: writing the memo, not building the thesis
A note on scope: this module is about WRITING the memo — its structure, the thesis paragraph, and the failure modes that sink one. What an investment thesis IS and how to construct one is owned by Practitioner Toolkit: From Concept to Thesis › Anatomy of an Investment Thesis. Treat that as the prerequisite; here we assume you already hold a thesis and focus on committing it to paper well.
The six sections of an investment memo
| Section | Purpose | What a strong version contains |
|---|---|---|
| 1. Thesis (one paragraph) | Commit to a falsifiable view: what is mispriced, by how much, and what closes the gap | Edge in 2-3 sentences; expected return with rough timeline; one-sentence statement of what would prove the thesis wrong |
| 2. Business description | Establish what the company actually does, how it makes money, and where its profit pool sits | Unit economics (revenue per customer, gross margin, fixed-vs-variable cost split), segment economics if multi-business, competitive position in a defined market |
| 3. Financial summary | Anchor the historical and forecast numbers the rest of the memo will reference | 5-10 years of revenue / EBITDA / FCF / ROIC / leverage; named drivers behind each trend; quality-of-earnings flags (one-time items, accounting changes, segment re-classifications) |
| 4. Valuation (triangulated) | Translate the financial view into a price target with a defensible range | Three methods (DCF, comps, precedent or sum-of-parts) with sensitivity tables; explicit reconciliation of the range to a recommended price; reverse-DCF cross-check on the current price |
| 5. Catalysts | Name the events expected to close the price-value gap and their rough timing | Time-bound and specific (earnings revision, regulatory decision, capital-return announcement, segment divestiture); identifies the chain from event to price re-rating |
| 6. Risks and downside case | Pre-commit to what would make the author wrong and what the loss looks like if so | Three to five specific risks (not boilerplate); a quantified downside-case price target; explicit asymmetry calculation (upside vs downside in same currency) |
Why the thesis paragraph carries the memo
The single highest-leverage section is the thesis paragraph. A memo whose thesis paragraph is precise ("this stock trades at 12x earnings against a peer group at 18x because the market is over-discounting the temporary margin compression from the 2024 raw-material cycle; as input costs normalize over the next 12-18 months, the company should re-rate to peer multiples; expected return roughly 50% over 18 months; the thesis is wrong if the margin compression proves structural rather than cyclical") forces every later section to be tested against a concrete prediction. A memo whose thesis paragraph is vague ("a high-quality compounder available at a reasonable price") gives the author -- and you, the reader -- nothing to falsify. The discipline of writing a 3-sentence thesis is the discipline of admitting whether you have an actual view. If you cannot write it, you do not have one.
The kitchen-sink and headline-only failure modes
The genre's most common failure mode is the kitchen-sink memo -- 30+ pages, every metric the author found interesting, no clear thesis, no quantified downside. The kitchen-sink memo is a defense mechanism: by including everything, the author transfers the analytical burden to the reader ("here is all the data; you decide"). Treat it as a red flag about the author's conviction. The opposite failure mode is the headline-only memo -- one page, no supporting work, a confident price target with no method shown. Both fail for the same underlying reason: they substitute volume or assertion for the work of committing to a specific, defensible view. A strong long-form memo is 8-15 pages, has a thesis you can quote in one paragraph, shows its method in valuation, and treats risks with the same seriousness as upside.
Write your thesis in exactly three sentences
Judging a thesis paragraph that says nothing
Why a description is not a thesis
Stop and re-read. "Well-managed franchise trading below book value with a long runway for compounding" is a description, not a thesis -- it names no edge (every value-investor memo about a bank says some version of this), no catalyst (what triggers the multiple re-rating), no time horizon, and no condition under which the author would be wrong. A memo whose opening commitment is this loose almost always inherits the looseness through the rest of the analysis: the financial section will list 10 years of book-value compounding without explaining why the market is currently discounting it; the valuation section will arrive at a range that brackets the current price; the risk section will list three boilerplate banking risks (credit cycle, NIM compression, regulation). The disciplined response is to re-read the thesis -- if it is genuinely as vague on re-read, your reading budget is better spent elsewhere. Going straight to valuation without a thesis frame leaves you with a number you cannot evaluate. Rejecting the memo entirely for one weak paragraph is over-strong -- the author may simply be a weak writer with strong underlying work -- but you should look for explicit catalyst and downside-case sections later to compensate.
The six questions every memo must answer
Which sections deserve the most page space
Four pathologies of poorly-written memos
Going deeper (optional). Up next: the four pathologies of poorly-written long-form memos — an advanced aside you can skip on first pass and come back to anytime. Continue when you're curious.
Going Deeper -- the four pathologies of poorly-written long-form memos. (1) Confirmation-bias structuring: the memo presents only data that supports the thesis, never the contradicting data the author had to reckon with; spot it by checking whether the risk section names specific empirical concerns or hand-waves through generic ones. (2) Backfilled valuation: the price target was decided first, then the DCF assumptions were tuned to arrive at it; spot it by checking whether the implied perpetual growth rate in the terminal value is internally consistent with the explicit-period growth assumptions, or whether they conveniently diverge to produce the desired number. (3) Vague catalyst language: "continued execution" or "steady improvement" are not catalysts; they are the absence of catalysts. A real catalyst is time-bound and specific. (4) Asymmetric coverage: 8 pages of upside, 1 page of downside, and the downside reads like a legal disclaimer rather than a serious quantification. The bull-bear asymmetry section in memo-2 fixes this. AI prompt for self-review: "Given this investment memo, identify the three weakest claims and the one piece of contradicting evidence the author chose not to engage with." The next module turns from structure to the catalysts-and-downside section that separates the genre's professional practitioners from its hobbyists.
Sit with the ideas.
You receive a 22-page sell-side investment memo on a small-cap industrial. You have 10 minutes before a meeting. What is the disciplined order in which to read it so you can form a defensible first opinion?