A recurring question at seed and Series A: do I need to write an investment memo, or is the pitch deck enough? The cleanest answer is that they are two sides of the same coin. Same story, different levels of detail. The pitch deck is the three-minute movie trailer. The investment memo is the three-hour feature film. If they contradict each other, you have a much bigger problem than which one to send.
An investment memo is the internal document a partner writes to convince the rest of the firm to fund your company. Historically, founders never saw it. Then a handful of firms started publishing anonymized memos and asking founders to write their own. Now it is a normal part of the process at Series A and above.
The memo is not a longer pitch deck. It is a structured argument that answers, in prose, every question a partner would ask during diligence. Length varies: five to fifteen pages is typical. Format is prose with occasional charts, not bulleted slides.
The important shift is that the memo is a decision document, not a marketing document. Its job is to help someone say yes or no with conviction, not to persuade someone who has not been paying attention.
It forces you to close the gaps in your deck. A pitch deck lets you gloss over hard questions with a clean chart. A memo does not. When you have to write, in complete sentences, why your CAC will drop 40 percent over the next 18 months, you find out very quickly whether you actually believe it.
It prepares you for diligence. By the time you get to a partner meeting, you will be asked most of the questions the memo answers. Writing the memo first means you already have the answers ready, written down, and consistent across meetings.
It gives the sponsoring partner ammunition. Even if you never send the memo, the partner championing your deal has to write a version of it internally. If you have already thought through the market sizing, the competition, the team gap analysis, and the risks, they can lift your framing directly. Deals get done because a partner can defend them in a Monday meeting.
The cleanest way to structure a memo is to use the same sections as your pitch deck, and expand each one with the detail that the slide had to leave out. Your deck is a 14-slide narrative; the memo is the details behind those slides. Concretely, six major sections mirror the deck''s six major arcs.
The deck slide answers "is the market big enough" in 30 seconds with a top-line number. The memo answers it properly. Include: the specific segment you are targeting (not the whole industry), a bottom-up market size built from reachable customers and realistic ACVs, the underlying trends driving growth, and a candid section on which parts of the market are not yours to win in the first three years. Investors trust founders who narrow the market more than founders who inflate it. Add a "why now" argument here.
The deck shows a screenshot. The memo explains what the product actually does, who uses it, how they use it, and what happens next. Include: a walkthrough of the core workflow, current feature set versus roadmap, the specific insight that makes your product different from every previous attempt at this problem, and any technical or data moat that gets stronger over time. If you have a demo, link it, but write the memo as if the reader will not click through.
The deck''s go-to-market slide names a channel. The memo defends it. Include: the primary acquisition motion, the evidence you have that it works (early CAC, payback, conversion rates, pipeline data), the second motion you plan to test with the round, and the reason competitors have not already captured the channel. If you have a design partner list, a pilot pipeline, or signed LOIs, this is where they go. Founders often bury the strongest evidence in an appendix. Do not.
This section separates good memos from great ones. The deck shows traction as a chart. The memo explains the operational playbook that produced the chart and can produce more of it. Include: your current sales motion in detail (SDR, AE, PLG, self-serve), the length of the sales cycle, how you generate pipeline, how you convert, what onboarding looks like, and what retention looks like after month three. If you have hiring plans, describe the exact roles you will fill with the round and why those hires unblock the next milestone. Investors are underwriting whether the playbook is repeatable at 5x the current volume.
The deck''s financials slide is a single graph. The memo is the model behind it. Include: the top three revenue drivers, current unit economics (CAC, LTV, gross margin, payback), monthly burn and runway, and a plain-language explanation of the assumptions in the projection. Then, in a separate paragraph, describe the two or three ways the model could be materially wrong. Naming the downside case is the single most credible thing you can do in a memo. Attach the actual model as an appendix.
Close with two short sections. The team section covers why this specific founding team is the right one to run this specific playbook, and names the two or three hires that would round out the gaps. The ask section covers the amount, the runway, the milestones the round funds, and what the next round will look like when you get there.
A memo is not the place for aspirational storytelling, quotes from thought leaders, industry-wide statistics with no source, or "TAM = $500B" slides in prose form. It is also not the place to hide bad news. Every experienced investor will find the churn cohort, the sales cycle that got longer, or the co-founder who left. Naming those in the memo, with your explanation of what happened and what you changed, is far better than having them surface in a reference call.
Send it early to partners you already trust. Some investors love reading a memo before the first call. It saves them time and gives you a better first meeting. Ask.
Send it as follow-up material after a first meeting that went well. This is the most common pattern. The deck earned the meeting; the memo earns the second meeting.
Do not send it. Just use it internally. Even in this mode, the memo pays for itself. Every question in the partner meeting will be one you have already answered in writing, and your answers will be consistent across the four or five investors you talk to that week.
The Rubik''s cube framing is a good mental model. Your deck is one face of the cube. The memo systematically works through all six faces, so that whichever side an investor turns, you have already thought through it. Founders who skip the memo often win their first meetings and lose their second ones. Founders who write the memo, even privately, tend to keep the momentum through diligence. That is the entire case for doing the work.
