So your pitch email landed. An investor opened it, read enough to be intrigued, and clicked through to your pitch deck. Congratulations, you’ve cleared the first hurdle that the majority of startups never get past.

Now the bad news: This is where most founders blow it. The Angel Investment Network Brokerage team have collectively spent decades raising capital for startups. They review hundreds of pitch decks every month and have identified a pattern of recurring mistakes that turn a promising first impression into a deleted email and ignored follow ups. If your email was the movie trailer, your deck is the film and too many founders are losing the audience before the first scene has played out.

Here are the mistakes that are killing pitch decks right now, and what the fundraising experts say you need to do differently.

1. No clear narrative and way too many slides

The most common mistake the brokerage team sees is a deck that fails to tell a compelling story. Instead of a crisp, captivating narrative that draws the investor in, founders load up slide after slide of detail without ever hooking the reader or focusing on style to mask a lack of substance. If your deck doesn’t immediately spotlight your core product and what makes it different from the competition, the investor has no reason to keep scrolling.

Length matters too. The brokerage team consistently flag decks that run beyond twenty slides as a red flag. Ten to twenty slides is the sweet spot. Go beyond that, and you risk losing the investor’s attention well before they reach your ask. Think of it this way, if you can’t distil your opportunity into twenty slides or below, you probably haven’t distilled your thinking either.

As Marisa Scullion, Head of Marketing at Angel Investment Network, puts it: “Your pitch deck is the ultimate marketing asset, and its sole job is to convert investor attention into action. Too many founders overload it with detail without telling a story or treat it like an art project, hiding a vague business model behind pretty graphics. Treat your ask as an undeniable Call to Action, and ensure your marketing asset delivers total clarity.”

2. Unclear traction: No proof the opportunity is real 

Investors need evidence that your startup has achieved some level of validated success and a clear pathway to growth. That means tangible metrics — user acquisition, revenue, partnerships — that demonstrate your startup’s potential beyond the pitch. Too many decks leave traction as an afterthought, burying it on a late slide or omitting it entirely. 

If you’ve got the numbers, lead with them. If you’re early-stage and the numbers are modest, frame them as momentum. The direction matters as much as the scale. Xavier Ballester, Director at Angel Investment Ventures, is unequivocal: “It is a very difficult market to raise in at the moment, especially at Seed and Pre-Seed stage. Traction is king as it gives investors comfort, so it’s key to show that your target market is using or buying your product or services. I recently looked at a pitch deck that had mentioned beta testing of the software but didn’t give a full low-down of the user stats – which were excellent – so it made me think it hadn’t been a success.” 

if you’ve got proof of traction, make it unmissable. Don’t assume the investor will dig for it. 

3. No customer pipeline: Even in the early days 

Even if revenue is still thin on the ground, or you are pre-revenue, investors want to see where your potential customers are coming from. A deck that shows ambition but no pipeline is asking an investor to take a leap of faith with no safety net. Ballester adds that for very early-stage companies, the bar is different but no less important: “If the company is very early stage, you may have to rely on market surveys to prove that the problem you are solving really is a problem.” 

Senior broker Alexander Caparros agrees, and gets specific: “If it’s early days in the revenue journey, it’s important to show where your pipeline of customer acquisition lies. Which customers or clients are you in negotiations, active discussion, or initial contact with, and what is the potential revenue from these? If clients are in the pilot stage, when can you expect it to convert to a contract or revenue?” 

A simple pipeline slide showing who you’re talking to, at what stage, and the potential value is one of the most underused weapons in a founder’s deck. 

4. Lazy use of AI: A lack of original thought

AI tools have made it easier than ever to produce a polished-looking deck. But investors can spot the difference between a founder who deeply understands their market and one who has outsourced their thinking to a chatbot. When the questions come, and they always do, the cracks show fast.

Senior broker Matthew Louis from the AIN Brokerage has seen this first-hand: “I recently came across a great opportunity solving a key pain point within its industry. However, when questioned on the market and its competitors, it was evident that this slide had been generated totally through AI leaving the entrepreneur unable to answer questions. It became clear they were also unaware of competitors’ features that solved the same issue. Using AI can be a game changer but make sure you are inputting the data and facts and you know what you’re saying.”

Use AI to refine your deck by all means, but never as a substitute for understanding your own market. If you can’t defend every slide in a live conversation, investors will know.

5. Financials that don’t add up

Your financial projections are one of the first things an experienced investor scrutinises. Numbers that are wildly optimistic, implausibly conservative, or just internally inconsistent will sink your credibility before you’ve had a chance to explain.

Louis is direct: “Your financials are a key area of focus for investors when looking at investment opportunities and if they don’t make sense, this serves as a major red flag. Similarly, having financials which are too high or low can be major issues – saying you’ll go from £1m to £15m in one year is just as worrisome as going from £100k to £1m in five years.”

Senior broker Alexander Caparros adds a practical tip: “Understand financial metrics and the differences between ARR, MRR and Revenue Run Rate. If it’s a SaaS business, a good financial metric that investors look at is Rule of 40: Annual Revenue Growth Rate plus Profit Margin needs to be 40%. It shows that management is focusing on growth and improving margins – showing this journey on a graph can do wonders.”

6. The team slide is an afterthought

Too many founders treat the team slide as a formality – a row of headshots with names and titles. But for investors, especially at the early stage, the team is often the single most important factor in the decision. They’re betting on people as much as the product, especially at an early stage. 

According to Caparros: “Put more information on the team than just a name. Where have the individuals worked? Do they understand this industry? Have they worked at any big companies, and is there evidence of previous scaling of a business or an exit? All of these will be signifiers that they understand the market and the business. When the going gets tough, this grounding will help them withstand the storms that come as a startup grows.”

Your team slide should tell an investor why these are the right people to execute this plan, not just who they are without context.

The pitch deck is where interest turns into action, or dies. Your email got the click, and that’s a real achievement. But the deck is where investors decide whether this is an opportunity worth their time, their money, and their network. Every mistake on this list is avoidable, and the founders who take the time to get these fundamentals right will dramatically increase their odds of turning an opened deck into a funded round.

Are you looking for an angel investor to help fund your business? Join us at Angel Investment Network, where global investors meet the great businesses of tomorrow.