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Lead your pre-seed pitch with this slide, and you have just told the investor you have nothing real to show them. At this stage, leading with this is not evidence, it is the thing founders reach for when they cannot yet point to the thing that actually matters. š©
You probably already know the slide. It turns up early in almost every first-time pitch deck. It carries one enormous number, meant to impress, borrowed from a report someone else funded. Founders deliver it with more confidence than anything else they say, because it is the one figure in the whole pitch that feels unarguably true.
It’s the slide that has your “total addressable market” size, or TAM.
“Our TAM is Ā£80 billionā.
I’m not saying that market size is irrelevant. And I really get the urge to lead with it at early stage. But the thing is: leading with it, this early, tells investors you are trying to sell vibes instead of your relentlessness to solve a real problem which you have true domain expertise.
And this is why fundraising strategy matters so much for early-stage tech startups: understanding what investors care about at each stage is key for spending your time and efforts smartly.
Do pre-seed investors actually care about TAM?
Less than you think, and almost never as the opening move or the main argument for getting investment.
By Series A or B, when you have real proof through numbers and real product and customer evidence, market size becomes part of a serious conversation about how big this can get. But at pre-seed you usually have not earned those numbers yet, so quoting a vast TAM does not prove anything. Everyone in the room knows the Ā£80 billion figure came from a report, not from you. It is decoration, and experienced investors read decoration as a substitute for substance, which in investor language means pure risk.
The contradiction every pre-seed founder has to navigate
Raising pre-seed is a genuinely strange place to be, because you have to prove two things that pull in opposite directions, at the same time.
One: that you have a unique insight into a specific problem, felt by a specific slice of people, and that you are the right person to solve it. This is narrow by definition, and it’s about depth, not breadth.
Two: that this very narrow, specific thing can become big, because it’s a part of a bigger picture. This is the opposite instinct, and it is about breadth and scale.
The TAM slide is founders trying to answer the second point while skipping the first. But at pre-seed the first point is where you win or lose the room, because it is the only one you can actually evidence right now.
Where market size does belong in a fundraising pitch
Market size matters when you can show the bridge.
The work is not quoting the big number, itās drawing the line between the small, specific market you are serving today (through a first client you helped or a few pilots you’re running) and the larger one it opens up if you continue in this path.
Who is your first customer, why do they need you now, and what does winning them let you reach next? If you can articulate that path, market size becomes a supporting argument. If you cannot, the TAM figure is pure decoration and everyone can tell.
So it’s not that the big TAM number is forbidden, it’s just that it canāt do the job on its own, and it definitely shouldn’t lead the conversation.
What actually moves a pre-seed conversation
Your team’s unfair advantage. That is the main thing at this stage.
Concretely, that means your unique insight into the problem space, plus proof that you have gone out of your way, repeatedly, to solve this problem for the people who care about it. Show customer conversations you ran. Talk about the imperfect things you built or tested that people paid to use anyway. Show evidence that you cannot stop working on this. That is what a genuine unfair advantage looks like, and no TAM slide can outperform that.
Paired with one more thing that founders underrate: enough self-awareness and confidence to name what you do not know yet. Yes, investors at pre-seed are buying potential, but potential does not mean abstract future earnings. It means a team’s potential to go big, shown through unique insight (the vision) and relentless effort (problem, customer, and solution validation), held together by the honesty to say where the gaps still are.
So… what to lead with instead of the TAM slide?
If you strip the Ā£80 billion off the front of the deck, this is what earns the room:
The specific problem, and the specific people who have it. The insight only you seem to have about why it persists. The proof you have already done the unglamorous work of validating it. Why you, of all people, are the one to solve it. And then, and only then, the bridge from this narrow wedge to a market worth an investor’s time.
Same information an investor needs, completely different logic.
Practising the tension is better than just reading about it
This is exactly the kind of trap I am building into the next chapter of Lumni Play, The Idea-to-Exit Simulator: a D2C femtech company, where the pull between “huge market” and “who is this actually for at early-stage” is precisely where founders can easily walk into trouble.
Reading about startup strategy is one thing. Making the call, in the chair, and watching how an investor reacts is another. That is what the simulator is for. It is free to play in the browser, no signup: play.lumni.work.
Working on this for real
The Idea-to-Exit simulator is free (for now), and it is deliberately low stakes, despite being a great learning tool. However, when the stakes are real, this is when you need someone at your corner, and that is exactly what I do at Lumni.
Lumni is a founder-side advisory practice based in London. I work with early-stage founders on overall strategy, early-stage validation, story and positioning ahead of a raise or an exit, which in practice usually means the work in this post: finding the sharp, specific thing that makes an investor lean in, and building the case around it in the right order.
If you are a UK-based tech team raising pre-seed in the next six to twelve months and the strongest slide on your pitch deck is about the potential market share, get in touch.
FAQ
Should I include TAM in a pre-seed pitch at all?
Yes, but not as your opening argument and not as a standalone number. Use it to show the bridge from the specific market you serve today to the larger one it opens up. On its own, a big TAM figure at pre-seed reads as filler.
What do pre-seed investors care about most?
The team’s unfair advantage: your unique insight into the problem, proof of relentless effort to validate it, and the self-awareness to name what you do not yet know. At pre-seed they are backing potential, not present-day revenue.
When does market size actually matter in fundraising?
It carries real weight from Series A onward, once you have traction and numbers that make a scale story credible. Earlier than that, evidence about you and your customer beats abstract market size numbers found on Google.
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