Small-cap stocks are popular in the UK with investors seeking exposure to high-growth companies. These types of stocks often deliver rewards far above the market average, but they can also expose shareholders to an elevated level of risk.
This guide will explain what small caps in the UK are, the advantages and disadvantages of investing in smaller companies like these, and three of the top UK small caps to buy today.
What are small-cap stocks?
A small-cap share can be categorised as a company with low market capitalisation and the potential for strong earnings growth. They tend to be early-stage companies that have scope to improve annual profits faster than more established businesses.
If you’re looking for small-cap stocks in the UK, you’ll need to look further afield than the FTSE 100 and the FTSE 250.
On the London Stock Exchange, the term ‘small cap’ refers to companies with a market capitalisation between £50m and £230m. This is vastly different from the United States, where stocks in this category have much larger market caps, ranging between $300m and $2bn.
Small-cap stocks can be found across a variety of UK stock indexes. There is a dedicated FTSE SmallCap Index, which contains scores of these smaller businesses and forms part of the FTSE All-Share Index.
However, while the FTSE All-Share contains around 600 stocks, small caps make up only a tiny number of the total. The index is predominantly made up of FTSE 100 and FTSE 250 shares that fall outside that £50m to £230m market-cap range.
Top UK small-cap stocks to buy
Here are three small-cap stocks for UK investors to consider in 2025.
| Small-cap company | Market Cap | Industry | HQ | Description |
| Luceco (LSE:LUCE) | £184.9m | Electronic & Electrical Equipment | London, UK | Designs, develops, and distributes wiring accessories, LED lighting, and portable power products. |
| Tristel (LSE:TSTL) | £139.5m | Healthcare Providers | Snailwell, UK | Manufactures infection prevention products for hospitals and clinics worldwide. |
| Atlantic Lithium (LSE: ALL) | £52.8m | Metals & Mining | Sydney, Australia | Explores and develops lithium assets in West Africa. |
Luceco
Luceco owns and manages a diversified portfolio of brands specialising in various electrical products operating worldwide. This includes switches, sockets, circuit protection, cabal management, commercial lighting, and portable power solutions.
Its brand portfolio includes Luceco LED Lighting, BG Electrical, Masterplug, Ross, and Sync EV. Combined, its solutions have helped bolster revenue and earnings through a combination of organic and acquisitive channels targeting commercial as well as consumer customers.
Looking to the future, management has highlighted its ambitions to further penetrate the home energy management market, with a projected 1.1 million electric vehicle chargers expected to be installed by 2030.
Tristel
Tristel specialises in the prevention of infections through its portfolio of chemicals and healthcare products. The firm’s flagship chemical is its proprietary chlorine dioxide, used for a variety of applications, including the decontamination of medical devices (under the Tristel brand) as well as surface disinfectants (under the Cache brand) serving as an alternative to traditional wet wipes.
Despite being a small-cap enterprise, Tristel is currently the market leader for medical device decontamination across Europe. In recent years, management has been expanding its footprint in North America to attempt to replicate its past success under the new CEO, Matt Sassone, who took over in September 2024.
Atlantic Lithium
Atlantic Lithium traded under the name of IronRidge Resources up until November 2021. The business is involved in the discovery of lithium in West Africa, an important element used in the manufacture of batteries. Demand for the element is tipped to soar as sales of electric vehicles take off.
Atlantic Lithium has described the West Africa region as a “new lithium frontier“. Its flagship asset is the Ewoyaa project, a high-grade source in Ghana. Testing work here has been consistently positive, and recent drilling has revealed the potential to expand the resource.
The asset currently has a mineral resource of some 30.1m tonnes and an estimated mine life of just over 11 years. And it is located close to critical power and transport infrastructure, including a major highway. It is within 70 miles of the port city of Takoradi.
Through an agreement with Piedmont Lithium, Ewoyaa is funded all the way through to production. In exchange for the funds to fast-track the asset, Piedmont — which owns a near-10% stake in Atlantic Lithium — could earn up to 50% of the small cap’s lithium portfolio in Ghana.
Advantages of small-cap stocks
There are multiple advantages to investing in small-cap shares.
- Larger Growth Potential – Since these businesses are far smaller, they can offer investors greater growth potential compared to mature large-cap enterprises.
- Lower Stock Prices – Small-cap shares often trade at a much lower share price, which can eliminate barriers to entry for investors with smaller sums of capital.
- Greater Diversification – There are more publicly listed small-cap stocks than mid-cap and large-cap shares, granting investors more choices and variety in diversifying their portfolios.
- Undiscovered Opportunities – Due to regulatory restrictions, most small-cap shares don’t have a high level of institutional ownership. As such, they’re typically not as widely followed by the financial media, enabling prudent investors the ability to discover terrific buying opportunities before everyone else notices, maximising long-term returns.
- Tax Advantages – In the UK, some small-cap stocks aren’t large enough to be listed on the Main Market and are instead listed on the Alternative Investment Market (AIM). Whenever investors buy shares on the AIM, there is no stamp duty tax to be paid, reducing transaction costs.
Disadvantages of small-cap stocks
There are a few risks related to small-cap shares to be mindful of.
- Weaker Financials – Many also don’t generate any profits. This means they have less financial clout to use to pursue growth opportunities. They often also lack the economies of scale that large-cap stocks can benefit from.
- Higher Volatility – They can soar when good news comes in but sink when times get tough. Therefore, investing in small caps may not be suited to individuals who either can’t or don’t want to own a stock for several years at least.
- Lower Liquidity – Due to lower levels of media coverage, the average trading volume for small-cap stocks can be relatively low, making shares far less liquid. This translates into wider bid-ask spreads that can harm investment returns.
- Less Regulatory Oversight – Companies listed on the AIM are subject to a less strict set of rules when it comes to regulatory filings compared to firms listed on the Main Market. While still rare, this increases the odds of a fraudulent company.
- Less Analyst Coverage – Since institutional investors don’t often explore the small-cap space due to regulatory ownership constraints, the amount of analysis and research available on small-cap stocks is often far more limited compared to large-cap stocks.
Are small-cap stocks right for you?
The rewards of investing in small market cap stocks can be huge if a company can identify a market opportunity and exploit it effectively.
Take Alpha Group International (LSE:ALPH), for example. The foreign exchange risk management and alternative banking fintech company started off as a £64m AIM-listed small cap in 2017. However, after carving out a niche within its industry, the firm quickly expanded and, within eight years, joined the prestigious ranks of the FTSE 250. Today, it has a market cap that is just shy of £1 billion.
Many other small caps have exposure to industries and trends that could lift their value through the roof in the coming decades. Some of the predicted hot growth industries of tomorrow are:
- Automation and robotics
- Green technologies (including electric vehicles and renewable energy)
- Healthcare
- Management consultancy
Smaller companies can be an excellent choice for investors who are happy to hold them for the long haul. But the high rate of failure of these companies — and the extreme choppiness of their share prices — mean that investors need to tread carefully before splashing the cash.