The hundred points
A cap table is a closed system. It holds exactly one hundred points of ownership — never 99, never 101 — so every point handed to a new investor or a new engineer must come out of someone else's column. Founders who negotiate valuation are watching the wrong number. Here is the arithmetic, worked all the way through.
Why smart people get this wrong
Cap table arithmetic defeats people who can price a bond in their head. The reason is structural, and it is worth naming before we touch a number.
Percentages are defined on a base that the transaction itself changes. If you want to give a new hire five percent of the company, you cannot simply take five percent of today's share count and issue it — because issuing those shares enlarges the company, and your new hire now owns five percent of a smaller thing. The answer depends on itself. That recursion is the whole difficulty, and it shows up again, disguised, in the option pool.
The second difficulty is a category error. A financing round has two outputs: a valuation, which is a headline, and an ownership split, which is a legal fact. First-time founders negotiate the headline. Experienced ones negotiate the split. By the end of this piece you will be able to show that the same investor cheque can produce a bigger headline and a worse outcome — and to compute exactly how much worse.
Two clocks, one event. Pre-money is what the business is agreed to be worth immediately before the money lands. Post-money is that figure plus the cheque. If a company is valued at $8M and raises $2M, the pre-money is $8M and the post-money is $10M. The investor's ownership is always measured against the post-money number: $2M / $10M = 20%.
Pricing a round in three moves
Two founders incorporate and take 1,000,000 shares each — a fifty-fifty split, 2,000,000 shares in issue. A seed fund offers $2M at an $8M pre-money valuation. We will price it as a priced equity round, because a priced round makes every mechanic visible. (Most real seed money arrives as a SAFE, which defers this arithmetic rather than avoiding it — more on that at the end.)
Three steps, in strict order. Each one feeds the next.
pre-money cap = 2,000,000 shares
② Price per share — spread the pre-money valuation over those shares
PPS = $8,000,000 ÷ 2,000,000 = $4.00
③ New shares — the cheque, divided by the price it buys at
new shares = $2,000,000 ÷ $4.00 = 500,000 shares
| Holder | Shares before | % before | New shares | Shares after | % after |
|---|---|---|---|---|---|
| Founder A | 1,000,000 | 50.00% | — | 1,000,000 | 40.00% |
| Founder B | 1,000,000 | 50.00% | — | 1,000,000 | 40.00% |
| Seed investor | — | — | 500,000 | 500,000 | 20.00% |
| Total | 2,000,000 | 100.00% | 500,000 | 2,500,000 | 100.00% |
Dilution is a multiplier, not a subtraction
This is the single most common modelling error, and it costs people real money in later rounds. Dilution is the share of the post-transaction company represented by the newly issued stock: 500,000 / 2,500,000 = 20.00%. It does not get subtracted from your stake. It gets multiplied into it.
right → 50% × (1 − 0.20) = 40.00%
Each founder keeps 0.80 of whatever they had. Hold onto that retention factor — in Section Six we multiply four of them together and the result surprises most people.
Hiring without a pool, and the arithmetic trap
The company lands its first engineer and offers her five percent. There is no option pool, so the board must authorise and issue fresh shares. How many?
The instinct is 2,500,000 × 5% = 125,000. That is wrong, and it is wrong in a specific direction — it shortchanges the employee. Issue 125,000 shares and she ends up with 4.762%, not five percent, because her own shares enlarged the denominator she is measured against. Solving the recursion gives 131,579 shares — 6,579 more than the naive answer.
| Holder | Shares | % before hire | % after hire | Change |
|---|---|---|---|---|
| Founder A | 1,000,000 | 40.00% | 38.00% | −2.00 pp |
| Founder B | 1,000,000 | 40.00% | 38.00% | −2.00 pp |
| Seed investor | 500,000 | 20.00% | 19.00% | −1.00 pp |
| Engineer | 131,579 | — | 5.00% | +5.00 pp |
| Total | 2,631,579 | 100.00% | 100.00% | — |
The highlighted row is why option pools exist. The investor bought twenty points and now holds 19.00%, and will lose another slice with every subsequent hire. No fund will sign up to open-ended dilution from a hiring plan it cannot see. So the investor asks for the hiring plan to be priced into the round.
The option pool, and the shuffle nobody explains
The fix is an option pool: a reserved block of authorised-but-unissued shares, typically ten to fifteen percent of the post-round company, sitting on the cap table as its own line. Grants to employees come out of the pool rather than being newly issued, so the fully diluted share count does not move and nobody is diluted by a hire.
That much is uncontroversial and genuinely useful. The consequential part is a question the term sheet answers in a single clause: whose points does the pool come out of?
Market practice is to place the pool inside the pre-money capitalisation. The pool exists before the investor's money arrives, so it is spread across the pre-money valuation alongside the founders' shares — and the founders absorb all of it. The investor's twenty points are untouched.
Run it. The investor wants 20.00% and a 10.00% pool, so the founders' 2,000,000 shares must represent the remaining 70.00%. That fixes the fully diluted count, and everything else follows.
FDS = 2,000,000 ÷ 0.70 = 2,857,142.86 shares
② Pre-money cap now includes the pool — this is the load-bearing step
pre-money cap = 2,000,000 + 285,714 = 2,285,714 shares
③ Same $8M pre-money, spread over more shares
PPS = $8,000,000 ÷ 2,285,714 = $3.50 (was $4.00)
The pool has quietly repriced the round. The investor still writes $2M and still receives 20.00% — but at $3.50 per share instead of $4.00, a 12.5% discount. The $8M pre-money on the term sheet is not the price at which the founders' stock changed hands.
The number the term sheet does not print
Ask what the founders' existing stock is actually being valued at, and the fog clears. Multiply their shares by the real price per share: 2,000,000 × $3.50 = $7M. There is a general form, and it is the most useful single line in this piece:
Effective pre-money = post-money × the percentage retained by everyone who was already there. Here: $10M × 70.00% = $7M. The headline said $8M. The pool costs the founders $1M — 5 percentage points each — and none of it appears as a valuation concession.
Nothing here is underhanded. The pool is a real cost of building the company, and someone has to bear it; investors argue, reasonably, that hires made after their money arrives create value they have already paid for. But it is a price term dressed as an administrative one, and it is negotiable along two axes: the size of the pool, and which side of the money it sits on.
| Carve | Founder A | Founder B | Investor | Pool | PPS |
|---|---|---|---|---|---|
| Pre-money (standard) | 35.00% | 35.00% | 20.00% | 10.00% | $3.50 |
| Post-money (founder-friendly) | 36.00% | 36.00% | 18.00% | 10.00% | $4.00 |
Now the pool does its job
Hire the same engineer at five percent. Her 142,857 shares move out of the pool rather than being issued fresh. Fully diluted shares stay at 2,857,143. The investor is still at 20.00%, the founders still at 35.00% each, and the pool drops to 5.00%. Nobody was diluted by the hire — because the founders already paid for it, in advance, in Section Four.
One tidy postscript. If the company is acquired with pool shares still unissued, those shares are typically cancelled and everyone else's ownership rises. The size of that rise is routinely misstated. With 5.00% of the pool unallocated, each founder goes from 35.00% to 36.84% — a gain of 1.84 percentage points, which is a 5.26% relative increase. "Everyone gains five percent" is true only in the relative sense, and it is the kind of ambiguity that ends up in a distribution schedule.
Price your own round
Everything above is one path through a three-variable space. Move the variables. The bar at the top of the page redraws as you go, and the readouts give you the numbers you would need to argue your case in the room.
- Post-money
- $10.0M
- Price / share
- $3.50
- Fully diluted
- 2,857,143
- Each founder
- 35.00%
- Investor
- 20.00%
- Pool
- 10.00%
- Effective pre-money
- $7.0M
- Headline overstatement
- $1.0M
Two experiments worth running deliberately. First, set the pool to zero: effective pre-money equals headline pre-money exactly, which is the only configuration in which the term sheet's front page tells the truth about price. Second, hold the pool at ten percent and push the pre-money up: the gap between headline and effective widens in absolute dollars, because a fixed percentage carve costs more when the company is worth more.
The higher valuation is the worse deal
Here is the payoff. Two funds bid for the same $2M round. Fund A offers $8M pre-money with a 10% pool. Fund B offers $7.5M — half a million lower — with a 5% pool. Every founder's instinct, and most founders' actual behaviour, is to take Fund A.
| Term | Fund A | Fund B | Difference |
|---|---|---|---|
| Headline pre-money | $8M | $7.5M | −$0.5M for B |
| Option pool | 10% | 5% | — |
| Investor stake | 20.00% | 21.05% | — |
| Founders retain | 70.00% | 73.95% | +3.95 pp for B |
| Effective pre-money | $7M | $7.03M | +$25,000 for B |
Fund B's headline is $0.5M lower and it leaves the founders 3.95 percentage points better off. Those points are not static, though — they get diluted alongside everything else in the rounds that follow, so their eventual worth needs carrying forward. Push the company through the Series A, B and C in the next section and the seed-round gap survives at 0.4918 of its original size.
Taking Fund A's extra $0.5M of headline valuation surrenders 1.94 percentage points at exit. On a $500M outcome that is $9.71M — 19.4× the valuation difference the founders thought they were winning.
Retention factors multiply
Follow Founder A from incorporation to a $500M exit through a conventional financing path. Each round has an investor stake and a pool top-up; together they define a retention factor, and the retention factors compound.
| Round | Post-money | New investor | Pool top-up | Retention | Founder A | Stake value |
|---|---|---|---|---|---|---|
| Founding | — | — | — | — | 50.00% | — |
| Seed | $10M | 20% | 10% | 0.70 | 35.00% | $3.5M |
| Series A | $30M | 20% | 5% | 0.75 | 26.25% | $7.88M |
| Series B | $90M | 18% | 3% | 0.79 | 20.74% | $18.66M |
| Series C | $250M | 15% | 2% | 0.83 | 17.21% | $43.03M |
| Exit | $500M | — | — | — | 17.21% | $86.06M |
The four retention factors are 0.70 × 0.75 × 0.79 × 0.83 = 0.3442. Founder A keeps 34.4% of her starting ownership — 17.21% of the company, down from fifty. Now compare that with the additive intuition. Adding the dilutions gives 30 + 25 + 21 + 17 = 93%, which would imply she is left with just 3.5%. She actually holds 17.21% — 4.92× what that arithmetic predicts.
Both directions of this matter in a negotiation. Founders who add the dilutions panic early and raise too little. Founders who ignore compounding entirely are surprised at Series C to find their combined stake below the threshold where their votes decide anything.
What a percentage does not tell you
Everything above treats a percentage of the company as a claim on that percentage of an exit. It is not. The model here is the right first model, and it is incomplete in ways that reverse conclusions rather than merely refining them.
Preferred stock is usually paid back first. A 1× preference on a $2M investment takes $2M off the top before anyone else sees a dollar; a participating preference then also takes its percentage of what remains. In a modest exit the preference stack can consume the entire proceeds and every percentage in this article pays out zero. Ownership percentages describe the upside case only.
Most seed money now arrives as SAFEs or notes, which are promises to issue shares later on terms fixed now — valuation caps, discounts, most-favoured-nation clauses. They do not appear as shares until they convert, which usually happens at the next priced round, all at once, at prices nobody recalculated in the interim. The founder-visible number is often a stack of SAFEs whose combined dilution nobody has modelled until the Series A term sheet lands.
A cap table shows shares issued, not shares vested. A co-founder who leaves in month ten of a four-year schedule with a one-year cliff appears on the cap table and keeps almost nothing. Ownership and entitlement are different columns.
The preferred price we computed, $3.50, is not the price at which employee options strike. That comes from a 409A valuation of the common stock, typically a substantial discount to the preferred price because common lacks the preference and control rights. One company, two defensible per-share numbers, and a great deal of confusion in recruiting conversations.
Referee the memo
The source this piece is built on is a good one — clear, honest, and written by someone who prices these rounds for a living. It also contains errors, which is normal for anything with arithmetic in it and is the reason auditing is a skill rather than an insult. Three candidate defects follow. One of them is not a defect. Identify which, and quantify the other two.
Exercise 9.1 — Audit the source
-
The handbook states that when unissued pool shares are cancelled at acquisition, everyone's ownership increases by five percent. Is that right?
Show the resolution
Ambiguous, and materially so. Cancelling a 5.00% unissued pool moves each founder from 35.00% to 36.84%. That is 1.84 percentage points, not five, and a 5.26% relative increase, not five percent either. The general result is a relative lift of 1/(1 − pool) − 1. Percentage points and percent are different units and a distribution waterfall that conflates them will pay out the wrong amounts.
-
In the option pool cap table, the seed investor's shares are printed as 571,426 in one column and 571,428 in the adjacent column, for the same quantity. Which is right?
Show the resolution
Neither, quite. The exact figure is 571,428.57 shares, so 571,429 is the correctly rounded value. 571,426 is a transposition typo. Small, but a cap table that does not foot is a cap table nobody should sign against — and this is exactly the class of error that survives a confident read-through and dies instantly to a column total.
-
In the no-pool hiring example, the engineer's five percent is given as 131,578 shares. Verify it.
Show the resolution
This is the one that is not a defect. Solving x / (2,500,000 + x) = 0.05 gives 131,578.95. Rounding down to 131,578 yields 5.00% — correct to every decimal place a cap table displays. Flagging it would be a false positive, and an auditor who cannot distinguish a rounding convention from an error is as expensive as one who misses real mistakes.
Exercise 9.2 — The negotiation
You are raising $3M. The lead offers $12M pre-money with a 15% pre-money pool. Using the live model above:
- Compute the effective pre-money valuation and the price per share. State the gap against the headline in dollars.
- Your hiring plan needs only 8% of options over the next eighteen months. Find the pre-money valuation at which a 15% pool leaves you exactly as well off as this offer with an 8% pool — that number is your counter.
- The lead refuses to move the pool below 15% but will discuss where it is carved from. Quantify what a post-money carve is worth to you in percentage points, and argue whether that is a better ask than the valuation bump in part 2.
- Carry your answer to part 3 through the Series A, B and C path in Section Seven. Express it in dollars at a $500M exit, then say why that figure is more persuasive in the room than the percentage — and why it is also more misleading.
Built as a teaching artefact for an MBA data-driven decision making sequence. The conceptual spine — the hundred-point framing, the seed round worked example, the option pool motivation — follows Cap Table 101 by Ramy Adeeb in the 1984 Ventures Founders Handbook. The effective pre-money formulation, the pre-versus-post carve comparison, the multi-round compounding path, the exit-carried valuations, and the audit exercise are additions.
How the numbers were made
- Every figure in the prose, tables and captions is emitted by
compute.pyintotruth.jsonand substituted at build time. No number in this document was typed by hand. - The script asserts the accounting identities directly — post-money must equal fully diluted shares × price per share, investor dollars must buy exactly the investor's share count, and every cap table must sum to one.
- The closed-form used by the live model is checked against 2,000 randomised term sheets drawn from a seeded generator, to a tolerance of
1e-4. - Discrete tally marks are allocated by largest remainder, so the hundred marks always total exactly one hundred. The readouts carry the exact fractional values; where they disagree, trust the readouts.
Caveats
- Single share class, no liquidation preference, no participation, no anti-dilution, no debt. These simplifications are load-bearing and Section Eight says where they break.
- The financing path in Section Seven is illustrative, not empirical. Real dilution paths vary enormously by sector, geography and vintage.
- This is educational material about mechanics, not legal, tax or investment advice, and not a substitute for counsel who has read your actual documents.
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