Why are index funds better than active funds?

On average, they are not better — they are the market. But because they charge much lower fees, they tend to outperform most active funds over time. Research consistently shows that 85-90% of active managers underperform their benchmark over 15 years after fees.

What is the cheapest index fund in the UK?

Some of the lowest-cost options include Fidelity Index World (0.12% OCF), Vanguard FTSE Global All Cap (0.23%), and HSBC FTSE All-World Index (0.13%). ETF options like Vanguard FTSE All-World (VWRP) charge around 0.22%.

Should I invest in a UK or global index fund?

A global index fund provides broader diversification across thousands of companies in multiple countries. The UK represents only about 4% of global stock market capitalisation, so investing only in UK indices leaves you significantly underexposed to global growth.

How do I buy an index fund?

Open a Stocks and Shares ISA or SIPP with a platform like Vanguard, interactive investor, or AJ Bell. Search for your chosen index fund, and either invest a lump sum or set up a monthly direct debit.

Is now a good time to invest in index funds?

Time in the market beats timing the market. Research shows that investing consistently over long periods outperforms waiting for the perfect entry point. Start with regular monthly contributions and stay invested.

Index Funds Explained: Low-Cost Investing

Q: What is an index fund?

An index fund is an investment fund designed to track the performance of a specific market index — such as the FTSE 100, S&P 500, or MSCI World. Instead of trying to pick winning stocks, it holds all (or a representative sample of) the stocks in that index.

What Is an Index Fund?

An index fund is a type of investment fund that aims to replicate the performance of a specific market index. Instead of paying a fund manager to pick stocks, the fund simply holds all the companies in the index in proportion to their size.

For example, a FTSE 100 index fund holds shares in all 100 companies in the FTSE 100, weighted by market capitalisation. When the index rises, the fund rises. When it falls, the fund falls. No human judgement is involved.

Why Index Funds Win

The case for index investing rests on one powerful fact: most professional fund managers fail to beat the market over time.

The S&P SPIVA scorecard — the most comprehensive study of active vs passive performance — consistently shows that over 15-year periods, approximately 85–90% of actively managed funds underperform their benchmark index after fees.

This is not because fund managers are incompetent. In aggregate, they are the market — and after fees, they must underperform the market. Index funds simply capture the market return at minimal cost.

The Cost Advantage

Fees are the key differentiator:

Index funds: 0.06%–0.25% annual charge (OCF)
Active funds: 0.75%–1.50% annual charge

On a £100,000 portfolio over 30 years at 7% growth, a 1% fee difference costs over £75,000 in lost returns. Low fees are the single most reliable predictor of future fund performance.

Investment fees and costs comparison illustration — Understanding fee structures is crucial to maximising your investment returns.

Popular Index Funds for UK Investors

Global Equity

Vanguard FTSE Global All Cap Index (0.23%) — Over 7,000 companies across developed and emerging markets
Fidelity Index World (0.12%) — Tracks the MSCI World Index of developed market stocks
HSBC FTSE All-World Index (0.13%) — Broad global exposure at very low cost

UK Equity

Vanguard FTSE UK All Share Index (0.06%) — Complete UK market exposure
Legal & General UK Index (0.04%) — One of the cheapest UK trackers

Bond Funds

Vanguard UK Government Bond Index (0.12%) — UK gilts for portfolio stability
Vanguard Global Bond Index (0.15%) — Diversified global fixed income

How to Get Started

Choose a platform: Vanguard (low-cost, limited range), interactive investor (flat fee, wide range), or AJ Bell (flexible, good tools)
Open an ISA or SIPP: Shelter your investments from tax
Select your fund: A single global equity index fund is sufficient for most beginners
Set up a monthly contribution: Automate your investing to remove emotion and build discipline
Leave it alone: Resist the urge to check daily. Review annually and rebalance if needed.

AI trading bot analysing market data with neural network patterns — AI-powered tools are increasingly used to identify market patterns and automate trades.

The Endorsement of Warren Buffett

The world's most successful investor has repeatedly recommended index funds for ordinary investors. In his 2013 letter to Berkshire Hathaway shareholders, Buffett wrote that his instructions for his wife's inheritance were to put 90% in a very low-cost S&P 500 index fund. He has won public bets against hedge fund managers using nothing more than a simple index fund.