Start up funding rounds: Series A, B, C and D explained

Just started a new business in the UK? If you’re looking to turn an idea into a viable business concept or you’re taking the next step towards expanding, you might need to look into investment options.

One route to take is equity funding, which is designed to help start-ups, scale-ups and everything in between.

In this guide, we’ll walk you through the different stages of equity funding. We’ll look at start-up funding rounds from seed funding right through to Series A, B, C and D. This includes essential info on the typical investment at each stage, along with what business development phase each funding round is designed for.

And while you’re exploring financial solutions for your startup, make sure to check out the Wise Business account. It’s ideal for companies of all sizes, especially if you have big plans to go global.

If you're a business sending more than 100,000 GBP (or equivalent) monthly across different currencies, get in touch with the Wise Business sales team to discuss the best solutions for your needs.

Talk with Wise Business Sales Team 🚀

What is equity funding and how does it work?

Equity funding is the process of raising money to develop a startup or grow a business by attracting investors. The investor gets a share of the business equity in exchange for the investment.

This may mean the investor is entitled to a share of profits and assets, and it may even mean a seat on the company board and a say in key decisions. It all depends on the investment agreement.

Equity funding can be extremely important for fledgling businesses. It can give them that essential cash injection required to achieve any number of goals, including:

• Turning a concept into a saleable product or service
• Hiring skilled staff or expanding the team
• Setting up production and/or buying raw materials
• Building or upgrading premises
• Investing in research and development (R&D) to improve products and services
• Expanding to international markets.

It’s especially useful for start-ups who are unable to access the capital or other forms of financing needed to get their company off the ground.

Within the world of equity funding, investment is usually provided in stages - each targeting companies at a different growth or development level. You may also have heard of venture capital funding, which almost exclusively focuses on early-stage companies and start-ups.

Startup funding rounds - an overview

Equity funding is typically provided in stages, and these are known as funding rounds. Each is aimed at businesses at different stages of development, ranging from startups right through to companies on the brink of going public.

Together, these funding rounds form an investment pathway to help brand new startups grow into successful, profitable and fully-fledged businesses.

Let’s start our walk-through of startup funding rounds with a quick look at the basics of each stage:¹

Funding round	Business stage	Typical investment	Investor types
Seed	Concept, with a validated product or service	£100,000 to £2 million	- Venture capital firms - Angel investors - Crowdfunding platforms
Series A	Start-ups with growth potential	£2 million to £10 million	- Venture capital firms
Series B	Rapidly scaling companies	£10 million to £50 million	- Venture capital firms
Series C	Mature companies	£50 million+	- Private equity firms - Large venture capital firms - Hedge funds
Series D	Mature companies preparing for an IPO or sale	£37 million to £224 million²	- Venture capital and private equity firms specialising in late-stage investments

We’ll look at each stage in more detail below.

Seed funding

Business stage: concept, with a validated product or service and some customer interest.
Typical investment: £100,000 to £2 million¹

Seed funding is an essential part of the journey for many startups. Mainly provided by venture capitalists, angel investors and sometimes through crowdfunding, it aims to get the business off the ground. The funds can be used to turn a concept into a real-life product or service, expand the team or increase customer acquisition.

Key requirements

Startups have the best chance of securing funding in a seed round if they:

• Have a validated product or service
• Have some customer interest (or research and insight into their target market)
• Can demonstrate tangible progress, such as growing revenue or customers, or having a strong relationship with suppliers
• Have clear company ownership, a business plan and a shareholders’ agreement outlining roles and responsibilities
• Are compliant with regulatory requirements, particularly in relation to employees and suppliers.

The world of seed investment can be highly competitive, so only the startups best able to demonstrate high growth potential are likely to succeed.

Series A funding

Business stage: start-ups with growth potential
Typical investment: £2 million to £10 million¹

Once seed funding has been granted to get the business up and running, startups can begin to think about further investment. They may want to bid for Series A funding, which is typically provided by venture capital firms focusing on startups with high growth potential.

So what is Series A funding and what is it used for? It’s usually provided in order to scale business operations, optimise systems and processes, and/or to help the company enter new markets. The overarching objective is to accelerate expansion.

Key requirements

The requirements for obtaining Series A funding are more challenging than for seed funding, as investors tend to carry out in-depth due diligence. Startups must have:

• A strong data-backed pitch deck and strategic growth plan
• A scalable business model
• Impressive growth metrics, demonstrating year-on-year revenue growth
• Detailed financial and legal documentation
• Evidence of compliance with regulatory standards, such as GDPR for example.

💡 Read more about: Series A funding

Series B funding

Business stage: rapidly scaling companies
Typical investment: £10 million to £50 million¹

Series B funding is suitable for fast-growing companies which are seeking to shore up their place in the market and achieve ambitious expansion targets.

Again usually provided by venture capital firms specialising in scaling high-growth businesses, this funding is typically used for goals such as:

• Geographic expansion to new global markets
• Increasing market share and working towards a leading position in the market
• Acquiring competitors
• Building infrastructure.

Key requirements

As you’d expect with such sizable sums on the table, companies face many challenges in securing Series B investment. They’ll need to provide evidence of the following:

• Robust financial metrics
• A strong leadership team
• A solid and growing customer base
• A clear plan for using funding to drive growth, and for overcoming challenges and complexities associated with expansion.
• Internal audits, carried out to ensure financial and regulatory compliance
• Updated shareholder agreements and contracts with key partners
• Implementation of employee equity and benefits schemes, designed to attract the best talent
• Efforts to secure intellectual property.

Series C funding

Business stage: mature companies
Typical investment: £50 million+¹

Series C funding is the first of a handful of late-stage funding rounds, aimed at mature businesses. These will be companies wanting to achieve large-scale objectives or to kickstart growth in certain areas. The funding is often used by businesses preparing to go public or make acquisitions.

Funding at Series C is usually provided by larger institutional investors, such as major venture capital firms, private equity companies and hedge funds.

💡 Read our guide to: private equity vs. venture capital

Due to the significant sums involved, this level of funding is only provided to successful companies with an established track record and strong market position.

Key requirements

To secure Series C funding, companies need to:

• Demonstrate sustained growth and the capability to achieve ambitious targets for market diversification and/or dominance.
• Provide audited financial statements, intellectual property protections and updated shareholder agreements
• Demonstrate proficient management of complex governance structures
• Comply with UK corporate and financial regulations to the letter, with full evidence to that effect
• Provide detailed evidence of the company’s long-term strategy, competitive position and overall financial health.

Series D funding

Business stage: mature companies preparing for an IPO or sale
Typical investment: £37 million to £224 million²

For many businesses, funding rounds will end at Series C. But for others, there are some final stages.

Series D funding is provided by venture capital and private equity firms specialising in late-stage investments. These strategic investors have the resources to provide larger sums to help mature companies reach particular milestones.

One of the most common scenarios where Series D funding is provided is when a company is looking to achieve significant growth targets before launching an initial public offering (IPO). The company may also be preparing for a sale or acquisition, or be looking to expand into new product categories.

However, the need for a Series D funding round can also be a warning sign that the company isn’t performing well. It may be struggling to raise capital or hit growth targets, or be spending funds more quickly than expected.

Key requirements

To obtain Series D funding, companies need to be fully prepared for exhaustive due diligence checks. They’ll need to show:

• Consistent and predictable growth
• Strong financial metrics
• A solid exit strategy, such as an acquisition or IPO.

Grow your company and go global with Wise Business

While you’re researching funding options for your startup or small business, it’s also worth making sure you’re set up with the right business account.

Open a Wise Business account and you can hold and exchange 40+ currencies at once.

You can send fast, secure payments to 140+ countries, and get account details to get paid in 8+ currencies like a local.

Whenever you need to send, spend or exchange foreign currencies, you’ll benefit from the mid-market exchange rate, with low, transparent fees.

You’ll also benefit from all of these features with Wise Business:

• No ongoing fees, minimum balance requirements or foreign transaction fees
• Debit and expense cards for you and your team, which you can use in 150+ currencies
• Multi-user access for team members, with ways to control and manage permissions
• Pay up to 1,000 people at once with the Wise batch payments feature
• Integrate with your favourite cloud accounting solutions
• Use the powerful Wise API for automation and streamlining workflow
• Take advantage of Wise Interest to make your funds work harder when you’re not using them (capital at risk).

With a truly global account, you’ll be all set to grow your business worldwide.

Capital at risk. Growth not guaranteed. Wise Assets UK Ltd is authorised and regulated by the Financial Conduct Authority with registration number 839689. When facilitating access to Wise investment products, Wise Payments Ltd acts as an Introducer Appointed Representative of Wise Assets UK Ltd. Please be aware that we do not offer investment advice, and you may be liable for taxes on any earnings. If you’re uncertain, we urge you to seek professional advice. To find out more about the Funds, visit our website.

---

After reading this, you should have a better understanding of startup funding rounds and which business stage each is aimed at.

We’ve also looked at typical investment amounts, what the funds are typically used for and the key requirements investors are looking for when choosing enterprises to invest in.

---

Sources used for this article:

1. Harper James - Our guide to funding rounds for start-ups: from pre-seed to Series A-C
2. DealRoom - Understanding Series A, B, C, D, and E Funding Rounds

Sources checked on 28-April-2025