The UK’s public markets differ markedly from those in the US, offering an often overlooked opportunity for smaller US growth companies to access capital from established institutional investors at a much lower cost than in the US.
London has the most international issuer base in the world and is the dominant capital raising venue in Europe. In short: you do not have to be a unicorn to go public in London.
Reasons London may be a suitable listing venue
“Which market?” is one of the first decisions a board must make when pursuing a public listing. Between 2017 and mid-2025, 57 US-incorporated and operated companies listed on the London Stock Exchange, with a combined market capitalisation of $67.9bn and raising an aggregate of $8.6bn.
As of December 31 2025, 67 US companies were listed in London with a combined market value of $138bn. Six US companies joined the LSE in 2025, including the largest main market IPO of the year (by size of fundraise) and the largest placing ever completed on the Aim.
Listing in London offers several advantages to US companies, particularly for early-stage and growth companies.
Smaller company focus
The LSE operates multiple markets, each tailored to support companies at the different stages of their lifecycle. Growth companies are encouraged to engage with public markets, with Aim having a strong record of supporting smaller, growth-oriented businesses.
High-quality, active, long-only institutional investor base
Unlike US markets, where smaller companies can struggle for visibility, London offers an active investor base focused on growth opportunities.
The UK holds Europe’s largest dedicated capital pool with $470bn in assets under management — twice the size of the next largest market. London-listed micro-caps (under $250mn) also attract significantly more actively-managed investment, leading to stronger market support and easier access to follow-on growth capital.
Lower listing costs
For offerings under $100mn, total fees (excluding underwriting fees) are about four to five times greater in the US than the UK. Cost savings can make a meaningful difference, especially for growth-stage companies where capital efficiency is paramount.
Reduced ongoing reporting obligations
London-listed companies report to the market on a twice yearly basis, compared to quarterly reporting obligations imposed by US regulatory frameworks.
Lower litigation risk
Since 2008, only five class actions (including group litigation orders) have been filed against companies listed in London, with the court ruling in favour of the company in two of those cases. Legal and insurance costs therefore tend to be much lower.
Broader access to capital
London-listed companies raise follow-on capital more frequently and across a broader range of sectors than their US counterparts. From 2019 to the end of June 2025, London-listed micro-caps were almost twice as likely to return for follow-on capital.
Receptivity to secondary selldown at IPO
UK investors often view secondary selldowns as an expansion of liquidity and are happy to support it if shareholders still retain an acceptable level of shareholding.
Focus on quality over quantity
UK smaller company stocks are typically held by high-quality institutions committed to long-term investment and supporting sustained growth. UK micro-cap IPOs have historically outperformed their US counterparts because UK institutional investors pay closer attention to smaller companies.
More certainty through better price discovery mechanisms
The UK IPO process is more flexible and transparent than that of the US, leading to better price discovery and fewer IPO ‘pops’. London enables both connected and independent analysts to publish deal research, providing in-depth insights and valuation models that help investors assess investment opportunities effectively.
Lower investor churn
The more extensive price discovery mechanisms in London reduce first-day IPO churn, making investors far less likely to sell immediately after listing.
Common objections to a London listing from US-based companies
For US companies, listing on domestic exchanges might seem the obvious choice. Many companies are drawn towards a domestic US listing by the perception that the company can achieve a higher valuation and greater liquidity and/or better access to the market with the largest pool of capital in the world. However, a US listing may not always be the best option for smaller companies.
Valuation and liquidity
Many assume there is a liquidity gap between the UK and US markets, often due to comparing non-equivalent metrics. Total daily value traded on the markets will likely show a large gap between US and UK liquidity metrics because of the size differential. When adjusted for free floats, the UK and US liquidity profiles are comparable.
It is also commonly believed that companies trade at higher multiples in the US than in the UK based on aggregate price-to-earnings (P/E) ratios of the S&P 500 and the FTSE 100. However, when using a growth-adjusted multiple such as price/earnings to growth, UK and US stocks are shown to trade broadly in line and many UK-listed growth companies trade at a premium to their US peers.
Access to US capital
A US listing may offer access to US institutional investors, however it is frequently quoted that a company needs to have a minimum market capitalisation of $2bn-$5bn to attract investor attention. Conversely, micro-caps listed in London benefit from more active investor backing from institutional investors than their US-listed counterparts.
The LSE boasts the world’s most geographically diverse investor base of any exchange, which can help US companies establish a truly global presence and attract investment from around the world, including from US investors.
Approximately 41 per cent of the investor base investing in UK-listed companies is from North America and established mechanisms under US securities law allow companies not listed in the US to access US institutional capital.
In addition, there are numerous examples of US companies using London as a stepping stone and adding a US listing once they achieve appropriate scale.
What to consider next
The London markets offer a compelling opportunity for US companies. Forward-thinking boards should consider the advantages that those can offer to them and their stakeholders.
With its diverse pool of capital, supportive market infrastructure and lower regulatory burden compared to the US, the LSE provides a strong platform for growth.
Fiona McFarlane is a partner at Bird & Bird; with additional contribution from Chris Mayo, head of primary markets, Americas, at the London Stock Exchange