Raising investment is one of the most critical milestones for a startup, yet many founders fail to secure funding – not because their business lacks potential, but because their pitch deck fails to capture investor interest. Research by CB Insights shows that lack of investor interest is one of the top reasons startups fail, and a poorly structured pitch deck is often to blame. Investors typically spend less than four minutes reviewing a pitch deck, meaning founders have a small window to make a compelling case.

A well-crafted pitch deck isn’t just about presenting numbers – it’s about telling a clear, concise, and compelling story that convinces investors of your startup’s potential. In this article, we’ll highlight the 10 biggest mistakes founders make in their pitch decks and, more importantly, how to fix them.

1. Overloading Slides with Too Much Information

The Mistake:
Many founders try to pack every detail into their pitch deck, resulting in dense, text-heavy slides that overwhelm investors. This approach makes it difficult for investors to quickly grasp key information.

The Fix:

• Keep slides concise, focusing on one key idea per slide.
• Use bullet points and clear, structured headings.
• Leverage visuals, charts, and white space to improve readability.
• Aim for 10-15 slides – long enough to tell a compelling story but short enough to maintain attention.

2. Weak or Confusing Problem Statement

The Mistake:
If investors don’t fully understand the problem you’re solving, they won’t be convinced by your solution. Many founders use jargon or assume investors already understand the market gap.

The Fix:

• Clearly define the problem, who it affects, and why it matters.
• Use real-world examples or case studies to illustrate the pain point.
• Back up claims with data, such as industry reports or customer feedback.

Example: Instead of saying, “Our AI software streamlines business processes,” say, “Companies waste an average of 20 hours per week on manual data entry – our AI reduces this by 80%.

3. A Generic or Unconvincing Solution

The Mistake:
If your solution doesn’t directly address the problem or lacks differentiation, investors will lose confidence.

The Fix:

• Clearly articulate how your product uniquely solves the problem.
• Use case studies, user testimonials, or product demos to prove effectiveness.
• Show how you differ from competitors with a comparison table or competitive advantage slide.

4. Lack of Market Validation or Traction

The Mistake:
Many founders focus on potential market size but fail to show actual demand for their product. Investors want proof that customers are willing to pay.

The Fix:

• Highlight customer traction (e.g. paying customers, active users, or revenue figures).
• Include Letters of Intent (LOIs), partnerships, or testimonials.
• If pre-revenue, demonstrate strong market interest through waitlists, pilot programmes, or survey data.

5. Unrealistic Market Size and TAM/SAM/SOM Calculations

The Mistake:
Many startups inflate their market size, often citing the Total Addressable Market (TAM) without realistically assessing their Serviceable Available Market (SAM) and Serviceable Obtainable Market (SOM).

The Fix:

• Use credible sources (e.g. Gartner, Statista, industry reports) for market size estimates.
• Clearly break down TAM, SAM, and SOM to show realistic revenue potential.
• If possible, use bottom-up calculations rather than top-down projections.

Example: Instead of saying, “The global SaaS market is worth £500 billion,” say, “We are targeting UK-based SMEs in the retail sector, a £2 billion market with a realistic obtainable market of £100 million in the next five years.”

6. A Weak Business Model or Unclear Revenue Strategy

The Mistake:
Investors want to know how you will make money – yet some startups fail to present a clear revenue model.

The Fix:

• Include a business model slide outlining pricing, revenue streams, and monetisation strategy.
• If applicable, explain key metrics like Customer Acquisition Cost (CAC) and Lifetime Value (LTV).
• Show how your business scales over time.

Example: If you’re a SaaS company, state your monthly subscription pricing, expected churn rates, and growth projections.

7. Poor Financials or Unrealistic Projections

The Mistake:
Some startups either skip financials altogether or present unrealistically optimistic revenue projections. Investors look for data-driven projections, not wishful thinking.

The Fix:

• Present realistic, bottom-up financial projections for the next 3-5 years.
• Include key metrics such as gross margin, burn rate, and runway.
• Show assumptions behind projections to build credibility.

8. Neglecting the Team Slide

The Mistake:
Investors back teams as much as they back ideas – yet some pitch decks fail to highlight the experience and expertise of the founders.

The Fix:

• Clearly showcase who is on your team and why they are the right people to execute the vision.
• Highlight relevant experience, industry expertise, and past successes.
• If applicable, mention advisors or board members who add credibility.

Example: Instead of just listing names, provide key achievements, such as “Jane Doe, CEO – 10 years in fintech, ex-Stripe, led £50M product launches.”

9. Poor Design and Lack of Visual Appeal

The Mistake:
A cluttered, text-heavy, or poorly designed pitch deck can undermine credibility and dilute your message.

The Fix:

• Use a clean, consistent design with high-quality visuals.
• Keep fonts, colours, and formatting professional and readable.
• Consider using tools like Canva, Pitch, or professional designers.

Example: Compare a slide with five paragraphs of text to one with a bold headline, 3 bullet points, and a relevant image – which is easier to digest?

10. No Clear Ask or Next Steps

The Mistake:
Some founders fail to specify how much funding they need, how it will be used, or what the next steps are. Investors need clarity on the opportunity.

The Fix:

• Include a clear Funding Ask slide stating:
  • How much you are raising
  • How the funds will be allocated (e.g. product development, marketing, hiring)
  • What milestones you expect to achieve with this funding
• End with a call to action, such as a follow-up meeting request.

Example: “We are raising £1.5M to scale customer acquisition, expand the team, and enhance product features, targeting £5M ARR in 24 months.”

Conclusion

A strong pitch deck is clear, concise, and investor-focused. Avoid these 10 common mistakes, and you’ll significantly improve your chances of securing funding. Before your next investor meeting, review your deck against these principles to ensure it tells a compelling and credible story.

If you’re struggling to refine your pitch deck, consider using AI-powered tools or seeking expert feedback to maximise your impact.

What’s the biggest challenge you face in creating your pitch deck? Let us know in the comments!