What to Put in a Monthly Investor Update

Every update needs a fixed spine of financial metrics so investors can compare month to month without re-learning your format. The spine is nearly the same for every business model:

Gross margin deserves its own line rather than being folded into burn because it drives everything downstream. Contribution margin goes further: it subtracts variable costs, including acquisition spend, from gross margin, and the case for tracking it is that this is the number that tells you whether each incremental sale helps or hurts (Reformation Partners on contribution margin). For most investor updates, gross margin in the table plus contribution margin in the commentary is the right split: the table stays comparable month to month, the narrative carries the sharper measure.

Be careful not to confuse the two. Gross margin deducts cost of goods sold, while contribution margin deducts all variable costs, so a business can show a healthy gross margin and a much thinner contribution margin once sales commissions and performance marketing are counted (Golden Egg Check on the two margins). If your table quotes gross margin and your commentary quotes contribution margin, label both, or an investor will assume you are being loose with definitions.

Then add one or two leading indicators that match how your business earns. Pick them once and never rotate them:

• Subscription software: net revenue retention, which measures expansion against contraction and churn from an existing cohort (Klipfolio's SaaS metric guide).
• Self-serve or product-led: CAC payback period, the months until gross profit from a customer repays the cost of acquiring them (Wall Street Prep on CAC payback).
• Marketplace: transactions per active buyer, or take rate by side.
• Enterprise sales: pipeline coverage and average sales cycle length.

Two indicators is usually the ceiling. A useful test: if an indicator moved this month, would you change a decision? If not, it belongs in an appendix, not the email.

One warning on payback. The simple formula ignores churn, and cohort-based calculations routinely show payback 20% to 100% longer than founders expect, because churned customers leave acquisition cost unpaid (Eric Andrews on cohort payback). If you report a payback number to investors, either calculate it on cohorts or say plainly that it is the simple version.

The biggest difference between a strong update and a weak one is not the metric table. It is the two or three paragraphs that explain what moved.

Good commentary answers four questions in order. What happened: the line item, the amount and the direction, in both dollars and percentage. Why it happened: the component drivers, each named and quantified. What it means going forward: whether this is a one-time event or a trend that changes the forecast. What you are doing about it: a specific action or a deliberate decision to hold course. A vague explanation invites challenge; a decomposition backed by numbers is hard to argue with.

Here is the same miss written both ways.

Weak: "Revenue came in at $412K against a plan of $450K. Marketing spend was over budget."

Strong: "Revenue was $412K, $38K (8%) below plan. Of the gap, $25K came from two enterprise deals slipping into next month at the customer's request (both signed since month end), and $13K from lower self-serve conversion after a pricing page test. The test ended and conversion is back at the prior rate. Full-quarter revenue is now projected at 3% below plan, and marketing spend was $6K over because of the test."

The second version disaggregates the gap into named drivers with dollar amounts, separates timing from real loss, gives a forward number, and closes with a decision.

Set a materiality threshold before you write, for example any variance above $25K and 10% of plan, and ignore everything below it. Without a threshold you either explain every line or only flag the largest one, and both fail the reader. Commentary on the two or three gaps that matter is worth more than ten lines of restatement.

Two habits make this easier to sustain. First, collect the "why" during the month, not at the end of it: a running note in your finance file where each unusual movement gets one line of cause saves an hour of reconstruction. Second, write commentary only for controllable variances. You cannot act on a currency swing, but you can act on sales rep attrition, and investors know the difference.

Runway is the number investors scan first, and it is the most frequently fudged. State gross burn (total cash out), net burn (cash out minus cash in), cash balance and the resulting runway in months. Investors need to know exactly how much cash is in the bank, how quickly it is being spent, and when the company will need fresh capital or reach self-sustainability, and ambiguity in that section erodes trust faster than a weak result (RaiseMoney).

A worked example shows why the trailing average matters:

• Cash on hand at month end: $1,840,000
• Net burn, last month: $210,000
• Net burn, trailing three-month average: $185,000
• Runway at trailing average: 9.9 months
• Runway if next month repeats last month: 8.8 months

Report both, and say which one you are managing to. Investors will do this arithmetic themselves; if your number and theirs disagree, they will ask why, and you would rather the answer be in the email.

For businesses with recurring revenue, the burn multiple (net burn divided by net new ARR) is a useful second view because it shows how many dollars of cash you spend per dollar of new recurring revenue. Klipfolio's benchmark guide treats under 1x as the target, 1x to 2x as generally acceptable and above 2x as warranting action (Klipfolio). Use it if you sell subscriptions; skip it if you do not.

Cash reporting also needs a definition. Say whether the balance is total bank cash or usable liquidity after encumbered funds, deposits securing credit lines and taxes withheld. The distinction is the difference between a runway figure an investor can trust and one they have to re-derive.

Asks are the part of the update investors actually act on, and the part founders most often soften into vague wishes. "Let us know if you can help with hiring" produces nothing. "We are hiring a senior backend engineer in Austin; two warm introductions to engineers from payments infrastructure companies by the 20th would help" produces a list of names.

Durkin's template puts asks second, immediately after the summary, precisely because readers who stop after the first screen still see the request (Durkin's template). A workable format is three numbered asks, each with what you need, why it matters and by when.

Track whether asks were fulfilled and thank the investors who delivered by name in the next update. Durkin recommends this explicitly: public thanks encourage other readers to step up. It also quietly builds the record that you use investor help when it is offered, which matters when you ask for something larger later.

If an ask goes unanswered for two months, retire it or sharpen it. A request that sits in every update without response tells readers the list is decorative.

The template below is deliberately short. If a section has nothing material to say, delete the heading rather than padding it.

Subject: [Company] update, [Month]

Summary (3 to 5 sentences)
What happened against plan, in plain language. State whether the month
was above, on, or below plan and the single most important reason.

Cash and runway (four lines)
Gross burn: $X
Net burn: $X (trailing 3-month average: $X)
Cash balance: $X
Runway: X months, to [month] at the trailing average

Core metrics (table)
Metric | Plan | Actual | Variance | Prior month

Variance commentary (two or three items)
What happened, why, what it means forward, what we are doing.

Highlights (three bullets maximum)

Lowlights (one or two, each with what you are doing)

Asks (three, numbered, each with a deadline)

Thank yous (named investors who helped, and how)

Carta describes the same five-part shape for most updates: highlights first, then financial performance including burn, then customer wins (Carta's guide to investor updates). The template above keeps that order but adds explicit variance commentary, which is where most updates lose their value.

Two formatting decisions do most of the work. First, keep the metrics table identical month to month, including column order and rounding, so a reader can scan a year of updates and see a trend without re-reading labels. Picking three to five consistent metrics and reporting them the same way every month is the rule, and swapping metrics when results are unfavorable is noticed immediately (Carta). Second, keep the whole thing to one screen of email on a laptop. Anything longer belongs in a linked note.

What to leave out: cap table details, individual salaries, customer names without permission, internal disagreements, and any metric you have not defined for the reader before. Send by BCC or a proper investor relations tool rather than exposing the whole list in the to line, and anonymize sensitive customer names unless the recipient is bound by an appropriate agreement (RaiseMoney). If a board deck already covers the month, reference it rather than repeating it.

Take a subscription business that just closed its monthly review. The plan called for $450K revenue, 78% gross margin, $180K net burn and a $1.9M cash balance.

Actuals: revenue $412K, gross margin 75%, net burn $210K, cash $1.84M. The unit economics review shows CAC payback at 14 months, up from 11, because paid search costs rose while the new pricing page test ran.

The update writes itself from there. Summary: below plan on revenue, margin slipped three points, payback stretched, cash and runway are fine, and the pricing test that caused most of it has ended. Table: the five spine metrics with plan, actual, variance and prior month. Commentary: two items, the revenue gap with the $25K timing split, and the margin slip of three points traced to a hosting contract renewal at a higher rate, offset from next month. Asks: two introductions for the hiring pipeline and one request for a benchmark from any investor who has run usage-based pricing. Thank you: the investor who made the customer introduction that became last month's largest expansion.

To check the payback change, start from the formula: CAC divided by monthly gross profit per customer (Stripe on the CAC payback period). If CAC rose from $440 to $560 while monthly gross profit per customer stayed at $40, payback moves from 11 months to 14, which is exactly what the review found. Writing that arithmetic out in one sentence stops the follow-up question before it is asked.

CAC itself is where sloppy updates show up, because undercounting costs makes every downstream number look better. Fully loaded CAC includes sales and marketing salaries, commissions, ad spend, tools and agency fees, and companies that track only ad spend underestimate true CAC by two to three times (LTV-CAC Book's unit economics guide). If your update quotes a CAC that excludes salaries, say so.

If the writing is the bottleneck rather than the numbers, that is a workflow problem, not a judgment problem. A model can draft the first pass from your metrics file and prior updates in a consistent voice, and an analyst reviews it. Quanta Inference gives you one API key across text, image and embedding models for that drafting step, with an OpenAI-compatible interface (Quanta Inference). The numbers still come from your own books, and the judgment about what to say in a bad month stays with you.

A final decision rule to keep the habit alive: if a month looks too bad to write up, send it early rather than late. Investors forgive a miss they hear about on time. They remember silence.