The case for investing in small caps

Small cap stocks are often overlooked but, for that reason, they can reward patient investors over the long term.

“Small caps offer a rare combination of attractive valuations, growth, and diversification,” said Abby Glennie, co-manager, Aberdeen UK Smaller Companies Growth Trust. “We’ve also gone through market periods globally where the dominant tech themes have driven handfuls of mega caps to lead markets, but perhaps now is the time for market strength to broaden out. Or at least for investor allocations to broaden out from mega caps for risk diversification, as they become increasingly nervous on the artificial intelligence (AI) trade.”

Glennie highlighted that small cap stocks have held up surprisingly well this year in the face of the conflict in the Middle East – which, on paper, could have looked like a major headwind for smaller businesses.

The MSCI World Small Cap Index returned 18.2% in 2026 through to 25 August, outperforming the core MSCI World Index which gained 13.3% in the same period.

“We aren’t seeing risk-off market performance in the way many would expect,” said Glennie. “Part of this driver is that smaller companies are trading at significant discounts to their historical valuation levels.”

What are small cap stocks?

Investment bank Saxo Group defines a small cap stock as one with a market capitalisation (market cap) ranging between $250 million and $2 billion.

Not everyone categorises small caps in this way. The major index provider, MSCI, groups stocks into size categories according to the percentage of the investable market they cover in each individual country, rather than using an absolute figure as a threshold.

“When constructing the MSCI World Small Cap Index, MSCI looks separately at each developed market, such as the US, Japan, UK and Australia,” said Lynn Hutchinson, head of ETF and index solutions at Raymond James. “The large and mid-cap companies might make up around the first 85% of each country’s investable stock market.” Small caps then become the rest, and MSCI then combines the small cap stocks from each country into a single, market cap-weighted index.

Generally, though, the $250 million to $2 billion range is a good rule of thumb for thinking about small caps.

With exceptions, their smaller size means small caps are less globalised than larger stocks – they may, for example, be more tapped-in to the domestic economy of their home country than larger cap stocks.

Why invest in small caps?

Small caps can offer diversification, especially in the current environment where momentum investing has concentrated lots of portfolios into the world’s largest stocks.

“Small caps provide exposure to a much broader range of businesses, sectors, and growth drivers,” said Glennie. “Small cap benchmarks and portfolios tend to be very diverse in that way, not dominated by handfuls of stocks or one overarching theme.”

They also offer the potential for higher returns, though this comes with the caveat that you might need to be prepared to ride out periods of volatility.

“In my view, small caps shouldn’t be treated with fear but with healthy curiosity,” said Angeline Ong, senior investment analyst at trading platform IG.

Small caps also offer good value to investors at the moment. The MSCI World Small Cap Index has an average trailing price/earnings (P/E) ratio of 18.4, as of July 2026 – compared to 23.1 for the MSCI World Index, according to data from investment research firm Morningstar.

Are UK small caps good value?

The UK’s small cap sector in particular offers good value. It trades even lower – at just 15.6 times trailing earnings, according to Morningstar.

“We see opportunities across global small caps, but the UK remains especially compelling on valuations,” said Glennie. “UK smaller companies have experienced a prolonged period of investor neglect, and the asset class has been unloved.

“This has left valuations substantially below both their own history and many international peers,” Glennie continued. “At the same time, many UK listed small caps generate revenues overseas, giving investors access to international growth opportunities but at a discounted price awarded for its headline UK listing tag.”

UK stocks are widely undervalued, across the market cap spectrum. But its small caps are weathering the economic storms that 2026 has thrown. The FTSE 250 index (which is made up of mid-cap stocks) gained 10.6% in 2026 through to 25 August, while the FTSE AIM All Share Index (comprising the country’s smallest stocks) gained 6.4%.

“While macroeconomic uncertainty remains, this isn’t holding back the asset class in the way many market participants might fear,” said Glennie. “Many high quality UK small caps continue to deliver strong earnings growth, maintain strong balance sheets, and generate strong cashflows, as well as support shares through ongoing share buybacks.”

The risks of investing in small caps

MSCI highlights the fact that small caps can be more volatile than larger stocks. Additionally, they might be less liquid, which can make trading them more costly.

“If you’ve not done your homework, your due diligence… you could be caught offside and end up nursing quite large losses,” said Ong.

The lack of liquidity, Ong said, could mean you can’t sell a position you want to exit quickly enough just because there aren’t enough buyers on the other side.

“The risk with small caps is you might not have the flexibility if you want to get in and out quickly,” she said.

How to invest in small caps

It’s tempting to try to pick the small cap stocks you want to invest in, particularly as many of these might be businesses you’re familiar with yourself.

But this approach can exacerbate the risks of small cap investing. “We’d suggest [small cap investing] is best approached through a portfolio holding, rather than direct individual equities,” said Glennie. “This is because of the benefit of risk adjusted returns that you get through a managed portfolio, whereas at individual stock levels the risk level is much higher- so that strategy is perhaps only suitable for a certain type of investor.”

Tracker funds replicating some of the major small cap indices include the iShares MSCI World Small Cap UCITS ETF (LON:WLDS) or the Vanguard FTSE Global Small-Cap UCITS ETF (LON:VSML).

Active funds tracking global small caps include the Janus Henderson Horizon Global Smaller Companies Fund or the Invesco Global Smaller Companies Fund.

Investment trusts that focus on small caps include The Global Smaller Companies Trust (LON:GSCT) and Edinburgh Worldwide (LON:EWI).

For a focus on UK smaller companies, you could select Aberdeen UK Smaller Companies Growth (LON:AUSC). Top holdings as of 31 July include investment platform AJ Bell (LON:AJB) and construction firms Morgan Sindall (LON:MGNS) and Galliford Try (LON:GFRD).

If you do want to pick your own small cap stocks, Ong stresses the importance of sticking to companies, or at least sectors, that you understand very well.

“It’s not like buying Microsoft,” she said. “You really need to know what you’re buying.”