Built in Britain, Listed in America? The Challenge Facing UK Startups as They Scale

This week, British AI company Quantexa revealed that it is considering a multibillion-pound stock market listing in either the UK, the US, or potentially both.

Founded in London in 2016, Quantexa has grown into one of Britain's most valuable technology businesses. The company was valued at $2.6 billion in its 2023 Series F funding round and is now preparing for the possibility of life as a public company.

But the fact that the US remains firmly under consideration highlights a much bigger issue for the UK's startup ecosystem.

Britain has no shortage of ideas, founders or early-stage capital.

What happens when those businesses become scale-ups?

The Pull of American Capital

For ambitious technology companies, the attraction of the US isn't difficult to understand.

American capital markets offer enormous pools of investment, a large base of technology-focused investors and, in some cases, the prospect of higher valuations.

Quantexa CEO Vishal Marria acknowledged exactly that when discussing the company's options, pointing to both the greater availability of capital and potential valuation advantages in the US.

And Quantexa isn't the only British business looking across the Atlantic.

Manchester-based investment firm Northern Gritstone is opening an office in San Francisco to help its portfolio of UK deep tech and life sciences companies access American investors, customers and talent. The firm has already raised £382 million and five of its 35 portfolio companies have US backing.

There is nothing inherently negative about British companies attracting international capital. In fact, global investor interest is a strong endorsement of the quality of businesses being built here.

The question is whether UK companies should have to look overseas to find the depth of capital they need to reach their full potential.

Britain Is Good at Starting Companies

The UK's early-stage investment ecosystem is one of its greatest strengths.

Angel investors, venture capital firms and schemes such as the Enterprise Investment Scheme and Seed Enterprise Investment Scheme have helped create an environment where ambitious founders can access capital much earlier in their journey.

From April 2026, the Government doubled several EIS investment limits, including raising the standard lifetime company limit from £12 million to £24 million and the annual limit from £5 million to £10 million. The changes were specifically designed to help successful UK businesses continue accessing growth capital as they scale.

That matters.

But a company capable of becoming a global technology leader may ultimately require hundreds of millions, or even billions, of pounds in capital over its lifetime.

EIS can help start that journey. It cannot be expected to fund the whole thing.

The Scale-Up Challenge

This is where the conversation around British startups needs to evolve.

Creating more startups is important.

Helping more of them become global businesses is arguably even more important.

A company might begin with founder capital, raise through SEIS or EIS, secure venture capital and eventually attract institutional investors.

At every stage, its funding requirements become larger.

If sufficient growth capital isn't available domestically, looking towards the US becomes an entirely rational decision.

That doesn't mean Britain has failed. But it does raise an important question about how much of the value created by British innovation ultimately remains connected to the UK economy.

Can London Compete?

The Government has been trying to make the UK more attractive to companies approaching the public markets.

Listing rules have been modernised, the prospectus regime has been simplified and PISCES has been introduced to provide private companies with another route to liquidity before a full public listing. The Government has also introduced three years of UK Listings Relief and continues to promote London as a destination for high-growth businesses.

Those reforms matter because the competition for successful companies is global.

Founders will ultimately choose the market that gives their business the best chance of succeeding.

If London wants more British technology companies to list here, it needs to offer a compelling commercial reason for them to do so.

From EIS to IPO

There's also a bigger story here for early-stage investors.

When someone backs an EIS company, they're investing long before questions about international expansion or public markets are likely to arise.

They're backing the business when the outcome is considerably less certain.

If that company eventually reaches the point where major institutions are competing to invest, or where London and New York are both realistic options for an IPO, that represents an extraordinary journey.

And it demonstrates why the entire funding ecosystem matters.

Britain doesn't simply need more capital at the beginning of that journey.

It needs a clear path from startup to scale-up, from private investment to institutional capital, and ultimately from promising British business to global company.

Quantexa's eventual decision will belong to Quantexa.

But the fact that one of Britain's most successful technology businesses is weighing London against the US should make the wider investment community pay attention.

The UK has proved it can create world-class companies.

The next challenge is making sure it remains one of the best places in the world to grow them.