Series funding: how to navigate Series A, B & C funding rounds

If you’re looking to launch your startup or are in the early stages of raising finance for your business, you’ll likely have a long-term vision for significant growth. And that kind of growth needs investment.

Series funding is a multi-round process (Series A, B, and C) where startups raise capital from external investors, typically ranging from £1m to over £30m+, in exchange for 10-25% equity.

Whether you’re new to the business world or are considering series funding yourself, this guide will explain everything you need to know.

We’ll explore the key aspects of each funding round, the benefits and drawbacks to consider, and tips on how to secure series funding to get your business off the ground.

What are the current 2026 funding trends for UK startups?

2026 is starting strong for startup funding in the UK, moving from a period of “cautious recovery” into a high-growth phase.

According to data reported by Fintech Finance, UK startups raised $23.6bn in 2025 — a 35% increase compared to the previous year — and this has carried into 2026.

AI continues to dominate

Artificial intelligence (AI) is continuing to dominate the business funding landscape. Over 60% of all recent seed and series rounds involve companies that leverage the technology, with “agentic AI” (systems that can act autonomously to achieve outcomes, rather than just responding to prompts) being the most funded sub-sector.

High-growth sectors in 2026

AI is reshaping every sector, but specific industries are capturing the majority of investment.

• Fintech remains the largest sector by value (most notably, banking platform giant Revolut securing $2bn in 2025).
• Healthtech and biotech are experiencing a “renaissance” in precision medicine and AI drug discovery, with nearly 25% of VCs targeting reproductive health, oncology, and personalised medication.
• Driven by the UK’s 2026 mandatory climate disclosure laws, there is a lot of funding for ESG compliance platforms, carbon markets, and renewable energy infrastructure.

Changes in funding stages

After a dry spell, “megarounds” (large funding rounds that are typically $100m or more) have made a comeback. In just the first week of January, the UK has surpassed the 200-unicorn milestone, making it the third country (after the US and China) to reach this level.

But despite this strong rebound, there’s still a reported gap for Series B and C rounds, as UK firms still rely heavily on overseas investors for funding above £20m.

What is Series A/B/C funding?

The term “series funding” refers to a multi-round process where startups raise capital from external investors.

As you might have already guessed, series funding is primarily split into three main funding rounds – A, B and C. But what does each round entail, and how are they different from each other?

What is Series A funding?

Series A funding typically raises £1m-£15m to scale operations, requiring a minimum viable product (MVP) and a scalable business model.

The main purpose of this round is to help advance a business’s growth, intending to expand the team, develop products/services, further scale operations, and boost sales and marketing efforts. 

What is Series B funding?

Series B funding focuses on scaling a business that has already met its Series A milestones, with typical raises of £10m-£50m.

At the Series B funding stage, a business has found its product/market fit and needs help to expand further. This includes growing the team by hiring specialised talent and improving product/service offerings or capabilities.

What is Series C funding?

Series C funding is for companies that aim to expand to international markets, acquire other businesses or develop new products. Additionally, they may seek Series C funding to increase their business valuation before an initial public offering (IPO) or an acquisition.

Series C funding isn’t easy to come by, as only 18% of VC funding for UK businesses goes to Series C and beyond. To qualify for Series C funding, startups must demonstrate high revenue, healthy profit potential, and a significant market share.

What are the pros and cons of Series A, B, and C funding?

Startups and early-stage businesses pursue series funding because not only does it give them access to capital, but it also helps increase visibility among potential customers, employees, partners and future investors.

That being said, it doesn’t come without its drawbacks. Here’s a quick breakdown of series funding to help you see the bigger picture.

✅ The pros of Series A/B/C funding

• Access to capital: provides the cash that businesses need to build, grow and scale effectively.
• Boosts credibility: can attract talent, partners and even media attention (especially if the investor is well-known).
• Strategic support: investors also offer valuable guidance, mentorship and connection.
• Faster growth: businesses can move much quicker with investor funding than they would through bootstrapping.

❌ The cons of Series A/B/C funding

• Equity dilution: giving an equity stake to investors means giving up complete ownership of your business.
• Pressure to perform: businesses are expected to meet high targets, achieve milestones and deliver ROI within a relatively short period.
• Loss of independence: major VC investors often require board seats or rights on key decisions, which can reduce your freedom as a founder.
• Risk of misalignment: the goals of investors and founders may not always align (for example, exit timelines or growth strategies), which can lead to tension.

How should I prepare my startup for a Series funding round?

To get series funding, you can’t just jump in with little more than a business idea. Investors want to know why your business is worth investing in, what it brings to the table and how it fits in with the market.

There’ll be a lot you need to prepare for, so we’ve broken down some key practices to help you get started.

1. Know your metrics

Numbers are important in business, and investors will want to see that you’re tracking the right ones. Depending on your business model, this could include:

• Revenue and growth rate
• Customer acquisition cost (CAC)
• Lifetime value (LTV)
• Churn rate
• Active users or engagement

These numbers are important as they show that you’re tracking performance, learning from your data, and making smart decisions. Moreover, investors want to see how you interpret these numbers and what actions you’re taking as a result.

2. Build a strong pitch deck

As mentioned earlier, this needs to be a 10- to 20-slide presentation that details what your business is about. It should walk investors through:

• The problem your business aims to solve
• How your product/service will solve the problem
• The size of your target market
• Your competition
• Further details of your product/service
• The business and revenue model
• The people behind your team
• Financial information (including profit and loss details, a balance sheet and potential earnings)
• Current status, use of funds and exit strategy

Make sure to practice your pitch as well. You’ll need to explain your business clearly and confidently. Be prepared for tough questions about your market, metrics, competition and team. Doing mock pitches with mentors or fellow founders from your network can help you fine-tune your pitch delivery.

Ready to be pitch perfect? Make sure to check out our guides on how to create a pitch deck and how to write an elevator pitch.

3. Clean up your cap table

A cap table (short for capitalisation table) is a spreadsheet or table that outlines who has ownership in your company. It should demonstrate who owns what percentage of the business, the types of securities they have (for example, shares, options or warrants) and the value of those shares.

Investors are very likely to request a cap table as part of their due diligence process. Therefore, you should provide a clear, up-to-date version that clearly shows investors what their share will look like if they invest in the company.

If your cap table is messy or unclear, it can slow things down or even scare investors off.

4. Have a data room ready

A data room is a secure space (either physical or virtual) that stores sensitive business documents and confidential information, such as financial statements, user metrics, legal contracts, your cap table and your product/service roadmap.

Having a data room ready in advance can help speed up the fundraising process, as investors won’t need to keep asking you for files. It also shows professionalism and proves to investors that you’re organised and prepared, and are being genuine about how your business operates.

How do I identify the right venture capital partners for my sector?

To find the right VC partner for your business, you should look into experience, connections, and credibility in your sector — not just whoever has the most money. Here are a few ways to consider when looking for VC funding:

Research VC by focus

Start by looking at VC portfolios and what companies they’ve invested in recently. If they’ve backed multiple startups in your niche or sector, that’s a strong indicator that they’re a good match for you.

You can also use databases like Crunchbase, PitchBook, CB Insights, or AngelList — all of which let you filter by sector, stage, and geography. Many sectors also have lists, such as “Top 20 Healthtech VCs in 2026”, which can help you quickly identify the most active and relevant investors in your field.

Look beyond capital

Remember — it isn’t all about the money. Before you get caught up in valuation numbers or fund size, it’s important to evaluate what each investor can actually do for your business beyond the capital. Therefore, you should ask yourself:

• Do they have sector-specific expertise?
• Can they introduce customers, talent, or strategic partners?
• Do they have a track record of helping startups scale?

Check their investment thesis

Every VC firm has an investment thesis — sometimes explicitly written on their website, or implied through their portfolio and public statements. A thesis reflects the types of companies, markets, and business models they believe have the highest potential. Common examples are:

• Stage focus: some VCs prefer early-stage startups to shape them from the ground up, while others focus on growth-stage companies ready to scale.
• Sector/technology preference: a VC might specialise in fintech, AI, healthtech, or sustainable energy, and so are more likely to understand your challenges and bring relevant resources.
• Location: certain VCs focus on specific regions or markets, so even a perfect sector match won’t help if your location isn’t part of their playbook.

Look into their reputation

A VC’s reputation and working style can make a big difference in your startup’s growth. The best way to understand this is to go beyond public profiles and dig into real experiences. You can do this by:

• Talking to founders they’ve funded: reach out to startups in their portfolio and ask about the partnership (were the VCs actively involved, or were they more hands-off, slow to respond, or bureaucratic?)
• Attending industry events and panes: whether it’s speaking at a conference, webinar, or local meetup, you should observe how they communicate, their depth of knowledge, and whether they connect authentically with founders and peers.
• Checking their network: a well-connected VC can introduce you to potential customers, hires, co-investors, and acquirers. When talking to founders, ask about the usefulness of their network.

Prioritise fit (not just size)

While large, well-known VC funds can write large checks and bring brand credibility, they often come with trade-offs.

Bigger funds tend to have more formal processes, several stages of decision-making, and rigid investment criteria. This can mean slower timelines, less flexibility on terms, and fewer chances to get hands-on attention.

On the other hand, smaller or sector-focused VCs are often more deeply invested in your success early on. They typically have a clearer understanding of your market, are quicker to make decisions, and are more willing to roll up their sleeves and help with strategy, hiring, customer introductions, and further fundraising.

What happens after Series C funding?

Once a business goes beyond Series C, it typically means that it has garnered a significant amount of money and success.

However, there are still some avenues that can be taken to secure additional capital, including:

• IPOs: this is when a business offers its shares to the public for the first time on a stock exchange, allowing it to raise capital from new investors.
• Acquisition: the business is purchased by a larger company, which can help it grow further, gain new technology and enter new markets.
• Additional series funding: while Series C is often the final funding round for businesses, others may go on to raise funding through Series D, E and beyond.

Conclusion

Series A/B/C funding can offer startups the capital, connections and credibility they need to scale quickly and reach ambitious goals. 

However, it’s not a one-size-fits-all solution, as each round brings new expectations, greater scrutiny and less control over your business. So, before jumping in, make sure your business is ready, your numbers make sense, and you’re clear on what you want out of the deal.

That being said, if you’re confident in your business’s growth potential, have a strong team behind you and are ready to meet investor demands, series funding could be just what your business needs to accelerate growth.