Startup dilution explained: what three rounds really cost founders
A worked example of what pre-seed, seed and Series A really do to founder ownership - plus the three traps that make dilution cost more than the headline numbers suggest.
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Startup dilution is the reduction in the percentage of the company each existing shareholder owns when new shares are issued – and across a typical pre-seed, seed and Series A, founders who started at 100% commonly end up holding around 35-45% as a rule of thumb.
Founders tend to learn dilution the way people learn about tides: gradually, then all at once, usually while staring at a cap table the morning after a term sheet. None of the arithmetic is difficult. What is difficult is that the arithmetic hides in defaults – pool timing, preference stacks, convertible caps – that are negotiated before most founders know they are negotiable. This guide walks through what three rounds actually cost, why that cost is usually worth paying, and the three traps that make it cost more than it should.
What three rounds really cost: a worked example
Here is a stylised example using round sizes at the European medians across the rounds Sesamers tracks (€1.6M pre-seed median, €5M seed, €16.5M Series A). It is a worked illustration, not a statistic – real cap tables are messier – but the arithmetic is exact.
Two founders start with 100%. They raise a modest €0.8M pre-seed at a €4M post-money valuation: the investor takes 20%, leaving the founders 80%. They raise a €5M seed at €20M post-money and create a 10% employee option pool in the same round: the founders land on 52%, a stake worth €10.4M on paper. Then a €16.5M Series A at €66M post-money, with the customary pool top-up, takes them to roughly 38% – worth about €24.8M on paper.
| Round | Raised / post-money | Founders own | Paper value of founders’ stake |
|---|---|---|---|
| Start | – | 100% | – |
| Pre-seed | €0.8M at €4M post | 80% | €3.2M |
| Seed (+10% ESOP created) | €5M at €20M post | 52% | €10.4M |
| Series A (+ pool top-up) | €16.5M at €66M post | ≈38% | ≈€24.8M |
Read the two right-hand columns together, because they tell opposite stories. The ownership column says the founders lost 62 points of the company in three rounds. The value column says their stake grew almost eightfold, from €3.2M to €24.8M on paper. Both are true. That is the entire logic of venture dilution in one table.
Dilution is the price of speed, not a loss
The useful frame is that dilution is a purchase. In each round the founders sold a slice of the company to buy time-compression: hires made years earlier, markets entered before competitors, mistakes survived that would have killed a bootstrapped company. Whether the purchase was good depends entirely on whether the money made the whole pie grow faster than the founders’ slice shrank.
In the worked example it did: 38% of €66M beats 100% of whatever the unfunded version of the company would have been worth – if you believe the funding genuinely accelerated the business. That conditional is the honest part. Dilution at rising valuations is the price of speed; dilution at flat or falling valuations is just loss, and no reframing fixes it. Which is why the only real defence against bad dilution is the same as the defence against everything else: a business that grows between rounds.
Latest funding
| Company | Round | Lead | Sector | Amount |
|---|---|---|---|---|
| Ki 13 Climate · United Kingdom | Seed | HICO Investment Group | Climate | €4.3M |
| Conveo Martech · Belgium | Series A | DST Global Partners, Balderton Capital | Martech | €43.2M |
| iPronics Industry · Spain | Series B | Maverick Silicon, Light Street Capital | Industry | €108M |
| iPremom Health · Spain | Seed | Amadeus Capital Partners | Health | €15M |
| Pharosyn Health · United Kingdom | Seed | Moonfire Ventures | Health | €2.6M |
| HyImpulse Defence Tech · Germany | Series A | JOIN Capital, Ace Capital Partners | Defence Tech | €50M |
The three traps that cost more than the headline round
Trap one: the pool is created pre-money
When a term sheet says “a 10% option pool will be created prior to the round”, it means the pool’s dilution lands entirely on existing shareholders – you – while the incoming investor buys their percentage of the enlarged, post-pool company. It is a standard ask, and it quietly lowers your effective price per share below the headline valuation. It is also the most negotiable of the three traps, which is why it gets its own section below.
Trap two: liquidation preferences
Percentages describe who owns the company; preferences describe who gets paid first when it sells. A standard European 1x non-participating preference is benign – the investor takes back their money or converts to their percentage, whichever is larger. But stack several rounds of preferences, or accept participating preferred or multiples above 1x in a desperate round, and a sale at a middling price can return less to a 38% founder than the cap table implies – sometimes dramatically less. Your percentage is not your payout. The clause-level detail lives in our term sheet guide.
Trap three: SAFE and convertible stacking
Deferred-pricing instruments – SAFEs, convertible notes, BSA-AIR – postpone dilution rather than avoiding it. Each one converts at the next priced round, usually at its own cap or discount, and founders who signed three instruments at three different caps over two years routinely discover at the seed that they have already sold 25-30% of the company without ever seeing it on a cap table. The fix is unglamorous: model the conversion every single time you sign one. The instruments themselves are covered in SAFEs, convertibles and BSA-AIR.
Negotiating the pool
Because the pool is created from your side of the table, its size is worth real negotiation. Per Index Ventures’ “Rewarding Talent” research, companies typically create an ESOP of around 10% at seed on both sides of the Atlantic; US companies then top up to roughly 15% at Series A and 20-25% by Series D, while European companies tend to stay near 10% (Index itself recommends Europe move to 12/14/16% at A, B and C).
The negotiating move is not to fight the pool’s existence – you want a funded pool; it is how you hire – but to size it from evidence: a bottom-up option budget for the actual 18-month hiring plan, presented next to the investor’s default ask. A 10% pool justified by a plan beats a 15% pool justified by habit, and the 5-point difference comes straight out of your side. What the pool means for the people receiving it is covered in startup employee equity in Europe.
Modest, median or hot: the same percentages, different outcomes
Founders fixate on the percentage sold per round, but across scenarios the percentage band is surprisingly stable – as a rule of thumb, European priced rounds sell 15-25% of the post-money company plus pool. What varies between a modest, a median and a hot company is mostly the valuation that percentage is priced at, and therefore what the founder’s remaining stake is worth.
A modest path – smaller rounds, lower valuations – can leave founders with a similar percentage to our worked example but a fraction of the paper value, and less margin for error in the preference stack. A hot company inverts the logic: competition among investors lets founders sell at the bottom of the range at higher prices, so they keep more and what they keep is worth more. The uncomfortable corollary is that dilution outcomes are mostly determined by company performance, not negotiating technique. Negotiation protects you from the traps; it does not substitute for growth.
When to stop selling equity
Equity is the most expensive money you will ever use, and each round should face the same test: does this capital compress time enough to justify the slice? Several signals suggest the answer has turned negative – revenue can now fund growth at a tolerable pace; the next round would price flat or down; founder ownership is approaching the level where another round starts to threaten motivation and control; or the honest use of funds is “runway” rather than acceleration.
There are also alternatives that did not exist at this scale a decade ago: Atomico’s State of European Tech 2025 counted $5.6bn of venture debt in Europe in 2025 – 12.7% of all funds raised – evidence that a meaningful share of European scaling is now financed without selling shares. Debt has its own teeth, but for a company with predictable revenue it can fund growth that would otherwise have cost five points of equity.
Frequently asked questions
How much equity do founders give up per round?
As a rule of thumb, European priced rounds sell 15-25% of the post-money company, plus the option pool created or topped up alongside the round. Hot companies close nearer the bottom of that range; struggling ones nearer the top, at worse prices.
How much do founders own after Series A?
A common rule-of-thumb range after three rounds (pre-seed, seed, A) is 35-45% held by the founding team combined. In our worked example at the European medians, two founders land at roughly 38%.
Is dilution bad for founders?
Not inherently. Dilution at rising valuations trades percentage for absolute value – in our example the founders’ stake shrinks to 38% while its paper value grows nearly eightfold. Dilution becomes damaging when valuations stall, preferences stack, or instruments convert at forgotten caps.
Do SAFEs cause dilution?
Yes – deferred, not avoided. Every SAFE, convertible note or BSA-AIR converts into shares at the next priced round, at its cap or discount. Stack several at different caps and the combined conversion can quietly claim a quarter of the company before the seed investor even arrives.
Keep going
The stage logic behind these rounds is in what is a startup. From here, go clause-level with the term sheet guide, instrument-level with SAFEs, convertibles and BSA-AIR, and people-level with startup employee equity in Europe. For the round data behind the medians used here, see the fundraising data hub.
