What is Series A funding? What it takes to raise one in Europe
Series A investors buy a demonstrated growth machine, not promise - here is what European A rounds look like, what diligence interrogates, and what the round costs founders.
Also see more startups coverage: /category/startups/
Series A funding is the round at which investors stop buying promise and start buying a machine: capital – a €16.5M median in Europe, across the rounds Sesamers tracks – to scale a growth engine the company can already demonstrate works.
Everything about the A follows from that definition. The diligence gets quantitative, the terms get heavier, and the bar filters out most of the companies that cleared the seed bar comfortably. Below, I take apart what “a repeatable machine” means in practice, what European Series A rounds look like in 2026, what the diligence actually interrogates, why most seed-funded companies never raise one – and why that is a mechanism rather than a malfunction – plus what the round does to your ownership.
The repeatable machine
At seed, you proved that someone pays, and that the paying was starting to repeat. At Series A, the question changes shape: can you show that when you put money in one end of the business, growth comes out the other end, predictably enough to be worth accelerating? That is what investors mean by a repeatable machine – a demonstrated relationship between input and output.
Concretely, a Series A-ready company can usually say things like: we acquire customers through two channels whose costs we know; those customers reach payback within a period we can state; they stay, and the older cohorts prove it; and here is what doubling the sales team does to the numbers. None of it has to be perfect – Series A companies are still messy – but the shape of the machine has to be visible in the data rather than in the narrative.
This is why “we’ll raise an A in 18 months” is not a plan by itself. The A is not a reward for surviving the seed; it is a purchase of evidence that most seed-stage companies, through no dishonour, never produce. The stage logic behind all of this is set out in our pillar on what a startup is.
How big is a European Series A?
Across the rounds Sesamers tracks, the median European Series A is €16.5M, from a sample of 26 rounds – with outliers reaching €115M, which tells you how elastic the label has become. The step change from the €5M seed median (n=74) is the financial expression of the change in proof: seed money funds the search for the machine, A money funds the machine’s expansion.
The environment around those numbers deserves a paragraph. Per Atomico’s State of European Tech 2025, Europe raised roughly $44bn in 2025, essentially flat against $43bn in 2024 and $41bn in 2023 – a stable market, not a booming one. Stability is a very European talent; we could use a little less of it here. Within that flat total, capital has concentrated: Tech.eu counted €44.1bn across 1,740 deals in H1 2026, versus roughly 2,000 deals in H1 2024, and Bloomberg reported the median European round size up 32% from 2024 to 2025, driven by US capital. Fewer, larger, more selective rounds – the Series A squeeze in one sentence.
What Series A diligence actually interrogates
Seed diligence asks whether the evidence is real. Series A diligence takes the evidence apart. Expect weeks, not days, and expect the questions to cluster around three areas:
- Channel maths. Where do your customers come from, what does each channel cost, and what happens to those costs as you spend more? A single channel that works is a start; proof that it does not saturate at 2x spend is the actual question. Investors will rebuild your funnel from raw data, not from your slide.
- Unit economics. Gross margin as it really is (including the support and infrastructure costs we all like to leave out), payback periods by cohort and channel, and the trajectory of both. The number matters less than whether it is moving the right way and whether you know why.
- Retention. Cohort curves are the closest thing the diligence has to a lie detector. Do customers stay? Does net revenue retention hold up once the early-adopter cohorts wash out? A leaky bucket at Series A does not get fixed by the Series A.
Underneath all three sits the same instinct: the investor is about to pay for acceleration, so everything that accelerates – good and bad – gets examined. The softer half of the assessment, from team depth to market timing, is covered in what VCs look for.
Why most seed companies never get here – and why that is the design
The reality: the honest baseline comes from Dealroom, which tracked 3,075 European companies that raised seed funding in 2016-18: 6% had raised a Series A within 12 months, 18% within 24, 27% within 36, and 31% within 48. The cohort is dated – it predates the 2021 bubble and the correction – but no better European benchmark has been published, and the shape is durable: roughly one seed company in four graduates within three years.
The silver lining: it is tempting to read that as a 73% failure rate, and it is not. The venture model is a portfolio machine: seed investors deliberately fund many cheap experiments knowing most will not compound into venture-scale outcomes, because the few that do pay for the rest. The seed-to-A filter is that mechanism working, not malfunctioning. Companies that do not raise an A include profitable businesses, quiet acquisitions, and teams that correctly stopped – alongside the genuine failures. We take that apart properly in what percentage of startups fail.
The opportunity: the A is won or lost in the 18 months before you pitch it. If the machine is not emerging by mid-seed, your choice is to find it, shrink towards profitability, or wind down deliberately – and all three beat drifting into a bridge round with nine weeks of runway. Brutal, but useful: the companies that treat the filter as a deadline rather than a lottery are the ones that clear it.
What the A costs you: dilution and the pool top-up
As a rule of thumb, European priced rounds sell 15-25% of the post-money company, plus whatever the option pool adds. At Series A the pool question returns: investors typically require the employee pool topped back up – per Index Ventures’ “Rewarding Talent”, US companies run roughly 15% pools at A while European ones tend to stay near 10%, with Index recommending 12% at A – and the top-up is usually created before the round prices, so existing shareholders absorb it.
Here is the worked illustration we use across these guides (a stylised example at the medians, not a statistic). Two founders raise a €0.8M pre-seed at €4M post-money, leaving them 80%. They raise a €5M seed at €20M post-money and create a 10% ESOP, taking them to 52% – a stake worth €10.4M on paper. Then the Series A: €16.5M at €66M post-money, plus the pool top-up, leaves the founders at roughly 38% – worth about €24.8M on paper.
| Round | Raised / post-money | Founders own | Paper value of founders’ stake |
|---|---|---|---|
| Pre-seed | €0.8M at €4M post | 80% | €3.2M |
| Seed (+10% ESOP) | €5M at €20M post | 52% | €10.4M |
| Series A (+ pool top-up) | €16.5M at €66M post | ≈38% | ≈€24.8M |
Look at what the table actually says. The percentage halved, and the paper value multiplied by nearly eight. The good news is that dilution done at rising valuations is the price of speed, not a loss – but only if the valuation keeps rising, so the optimism has to be earned round by round. The full mechanics, including the traps, are in our guide to startup dilution, and the clause-by-clause detail in the term sheet guide.
Series A vs Series B: where the next line sits
If seed proves demand and A proves the machine, what is left for B? Proving the machine scales economically. A Series B investor assumes the engine works and interrogates what happens when it runs hot: do acquisition costs hold as spend multiplies, does the second product or market show the same physics as the first, can the organisation itself scale past a hundred people without the wheels loosening. The A buys the machine; the B buys its industrialisation. Companies that clear that bar start leaving startup territory altogether – see what a scaleup is.
So the target was never “raise a Series A” – plenty of good companies never do, and a few bad ones manage it anyway. The target is a business where growth responds to investment in ways you can measure and defend, whether the capital comes from a fund, from customers, or from patience. Build the machine first – the round will follow!
Frequently asked questions
How much is a typical Series A in Europe?
The median is €16.5M across the rounds Sesamers tracks (n=26), with outliers up to €115M. It is a small, announced-round sample, so treat it as a marker of the market’s centre of gravity rather than a target.
What metrics do you need for a Series A?
There is no universal revenue threshold, whatever the folklore says – bars vary by sector, geography and fund. What is universal is the shape: known acquisition channels with known costs, unit economics trending the right way, and retention cohorts that hold. Investors buy the trajectory and the mechanism, not a single number.
How much equity do you give up in a Series A?
As a rule of thumb, European priced rounds sell 15-25% of the post-money company, and the A usually adds an option pool top-up that existing shareholders absorb. In our worked example at the medians, founders go from 52% after seed to roughly 38% after the A.
How long does it take to raise a Series A?
Three to six months is the standard working assumption for a priced institutional round, with Series A diligence at the deeper end. Start with at least nine months of runway; raising from a position of scarcity is the most expensive way to do it.
Keep going
For the foundations, read what is a startup. Then work backwards through what a seed round proves, forward through what three rounds cost founders, and into the room with what VCs look for. To see who is actually writing Series A cheques in Europe right now, start with our most active investors hub.
