Investiční slovník
Market Capitalisation: What Small, Mid and Large Cap Mean — and Why It Matters
Key takeaways
- Market capitalisation = number of shares times current price.
- Large-cap companies are more stable but have lower growth potential than small caps.
- Small-cap shares are more volatile and less liquid — but have historically delivered a premium.
- ETFs exist for every category and across all three combined.
- In an index like the S&P 500, the largest companies automatically have an overweight.
Market capitalisation is the total market value of a company — calculated as the total number of outstanding shares multiplied by the current share price. It is the most widely used measure of company size on the stock exchange.
The cap breakdown: small, mid, large
The exact thresholds vary by index provider, but the general convention is:
- Large cap — companies with a market cap above roughly $10 billion. Stable, well-followed, less volatile. Typically household names.
- Mid cap — roughly $2–10 billion. The company is established but still has room to grow. A compromise between stability and potential.
- Small cap — below roughly $2 billion. Younger or more specialised companies, higher potential alongside higher risk.
There is also micro cap for the smallest publicly traded companies and mega cap for the absolute giants — but these terms are not standardised.
Why this matters for investing
Capitalisation is not just a number — it reflects what you expect from a share. Large-cap companies are like cargo ships: they move slowly but reliably. Small-cap companies are like speedboats: faster, but more sensitive to waves. Academic studies (notably the work of Fama and French) have historically suggested that small companies outperform large ones on average — at the cost of higher volatility and longer periods of underperformance.
Market cap and indices
Most well-known indices are market-cap weighted — the larger the company, the larger its share in the index. In practice this means an index like the S&P 500 is substantially tilted towards mega-cap names. If that does not suit you, there are equally-weighted or size-specific ETFs available.
The ETF route: access to every category
Both sectoral and global ETFs exist targeting purely large-cap, mid-cap or small-cap companies. Some funds combine all three categories. The key is to compare which index the fund tracks — even two "small-cap ETFs" can have very different compositions.
FAQ
What is market capitalisation in simple terms?
The total market value of a company. You calculate it as the number of outstanding shares multiplied by the current price. A company with one million shares at a thousand crowns each has a market cap of one billion crowns.
Are small-cap shares better than large-cap shares?
Historically they have delivered higher average returns, but at the cost of greater volatility and longer drawdowns. For a long-term investor, small-cap ETFs can make sense as a smaller portion of the portfolio — not as its foundation.
How do I find out what capitalisation range an ETF covers?
Look at the fund's name or fact sheet — it always states which segment it tracks. Also read the top ten holdings to verify they match your intention.