You’ve probably heard the term “FTSE 100” on the news or in conversation — maybe your parents mentioned it, or you caught a headline about it rising to a record high. But what is the FTSE 100, exactly? And more importantly, how do ordinary people actually invest in it?
Here’s the short answer: the FTSE 100 is the UK’s most famous stock market index, and it’s one of the most straightforward ways for beginners to get started with investing. Whether you’re in the UK or the US, this guide will walk you through everything you need to know — in plain English, no finance degree required.
What Is the FTSE 100?
The FTSE 100 — officially called the Financial Times Stock Exchange 100 Index — is a stock market index that tracks the 100 largest publicly listed companies in the United Kingdom, ranked by their market capitalisation. That’s a fancy way of saying it measures the total value of the 100 biggest companies trading on the London Stock Exchange (LSE).
You’ll often hear it called the “Footsie” (yes, that’s really its nickname). It’s maintained by FTSE Russell, a subsidiary of the London Stock Exchange Group (LSEG), and has been in existence since 3 January 1984, when it launched at a base value of 1,000 points.
“Think of the FTSE 100 as the UK’s version of the US S&P 500 — it’s the go-to yardstick for how the British stock market is performing.”
Today, the FTSE 100 represents approximately 80% of the total value of the UK stock market. When people say “the market was up today” in the UK, they’re almost always referring to the FTSE 100.
How Is the FTSE 100 Calculated?
The FTSE 100 uses a method called market capitalisation weighting. This means companies with a larger total market value carry more influence over the index’s daily movements than smaller ones.
Here’s how it works in practice. If AstraZeneca (one of the index’s largest constituents) sees its share price jump by 5%, it will have a much bigger impact on the overall FTSE 100 level than if a smaller company in the index rises by the same percentage.
The index is recalculated every 15 seconds during London Stock Exchange trading hours (8:00 AM to 4:30 PM GMT), giving investors real-time information on how the UK’s top companies are performing.
The Quarterly Review: Who Gets In, Who Gets Out
The FTSE 100 is not a fixed list. Every quarter, FTSE Russell reviews which companies qualify for inclusion based on their current market capitalisation. If a company’s value grows enough to push it into the top 100, it gets “promoted” into the index. Companies that slip below that threshold get “relegated” to the FTSE 250 — the index that covers the next 250 largest UK companies.
These quarterly reshuffles can cause significant price movements, as index-tracking funds are required to buy the new entrants and sell the departed companies to match the updated index composition.
What Companies Are in the FTSE 100?
Despite being called a “UK” index, many FTSE 100 companies are genuinely global businesses that happen to be headquartered in Britain. Around 75% of the revenue generated by FTSE 100 companies actually comes from outside the UK — from markets across North America, Asia, Europe, and emerging economies.
As of early 2026, three companies dominate the index by market capitalisation — AstraZeneca, HSBC, and Shell — together accounting for roughly 26% of the entire index. The top five companies by market cap (as of January 2026) are:
- AstraZeneca plc — pharmaceutical giant, the UK’s most valuable company at approximately £230 billion
- HSBC Holdings plc — Europe’s largest bank by assets, with massive Asia exposure
- Shell plc — global energy major and the UK’s biggest company by revenue
- Unilever plc — consumer goods multinational (Dove, Hellmann’s, Ben & Jerry’s)
- Rolls-Royce Holdings — aerospace and defence engineering group
FTSE 100 Sector Breakdown (January 2026)
| Sector | Index Weighting | Key Companies |
|---|---|---|
| Financials | 26.15% | HSBC, Barclays, NatWest |
| Consumer Staples | 15.15% | Unilever, Diageo, Tesco |
| Energy | ~12% | Shell, BP |
| Healthcare | ~11% | AstraZeneca, GSK |
| Industrials | ~10% | BAE Systems, Rolls-Royce |
| Materials | ~8% | Rio Tinto, Anglo American |
| Technology (limited) | ~3% | Sage Group |
One important distinction between the FTSE 100 and the US S&P 500: the FTSE 100 has much lighter exposure to technology companies. While the S&P 500 is dominated by Apple, Microsoft, and Nvidia, the FTSE 100 leans heavily on financials, energy, consumer staples, and healthcare. This gives it a very different risk and return profile to US indices.
Why Does the FTSE 100 Matter to Investors?
The FTSE 100 matters for three big reasons: diversification, income, and global exposure.
1. Built-In Diversification
When you invest in the FTSE 100, you’re instantly spreading your money across 100 of the UK’s largest companies in multiple sectors. You’re not betting on one company or one industry — you’re buying a slice of British blue-chip business. This diversification reduces the risk that any single company’s bad news will devastate your portfolio.
2. Reliable Dividend Income
The FTSE 100 is well known for its dividends. Unlike the tech-heavy S&P 500, where many companies reinvest all profits rather than paying shareholders, FTSE 100 companies have a strong tradition of distributing cash directly to investors.
As of 2026, the FTSE 100’s forward dividend yield sits at approximately 3.3%, and analysts at AJ Bell forecast that FTSE 100 companies will deliver a record total of £88 billion in dividend payments in 2026 — exceeding the previous all-time high of £85.2 billion set in 2018. HSBC alone is forecast to pay £10.7 billion, followed by Shell at £6.3 billion.
“For income-seeking investors, the FTSE 100’s combination of yield and blue-chip stability is hard to beat in developed market equities.”
3. Currency Diversification for Global Investors
Because so many FTSE 100 companies earn revenue in US dollars, euros, and Asian currencies, an investment in the FTSE 100 gives you indirect exposure to global economies. Interestingly, a weaker British pound often benefits FTSE 100 companies, because it makes their overseas earnings worth more when translated back into sterling.
How to Buy the FTSE 100: A Step-by-Step Guide
Here’s the key thing to understand: you cannot buy the FTSE 100 directly. The index itself is just a measurement — like a thermometer reading the temperature. What you can do is invest in funds that track the index and are designed to match its performance as closely as possible.
The two main vehicles are Exchange-Traded Funds (ETFs) and index funds. Both work by holding shares in all 100 FTSE 100 companies in the same proportions as the index.
For UK Investors
Step 1: Choose Your Account Type
The type of account you use to hold your investment determines how much tax you pay on your gains and dividends. For most UK investors, there are two smart options:
- Stocks and Shares ISA — Invest up to £20,000 per tax year with no capital gains tax and no income tax on dividends. This is the most popular option for straightforward long-term investing.
- Self-Invested Personal Pension (SIPP) — Contributions receive government tax relief (at least 25% added on top), and your investments grow tax-free. However, you generally cannot access the money until age 57 (rising from 55 from 2028).
- General Investment Account (GIA) — No contribution limits, but gains and dividend income are subject to tax. Best used once you have maxed out your ISA allowance.
Step 2: Choose Your Platform
You’ll need to open an account with a regulated UK investment platform. Popular options include Hargreaves Lansdown, AJ Bell, Vanguard UK, InvestEngine, and Fidelity UK. Each charges different platform fees, so it’s worth comparing before you commit. Look for:
- Low or no dealing fees on ETFs
- Low annual platform charges (typically 0.15%–0.45% per year)
- Regulation by the Financial Conduct Authority (FCA)
Step 3: Pick a FTSE 100 ETF or Index Fund
Once your account is open and funded, search for a FTSE 100 tracker. Here are the most popular options:
| ETF Name | Ticker | Expense Ratio | Type | Best For |
|---|---|---|---|---|
| iShares Core FTSE 100 UCITS ETF | ISF / CSPX | 0.07% | Distributing | UK investors (most popular) |
| Vanguard FTSE 100 UCITS ETF | VUKE | 0.09% | Both available | Vanguard fans, long-term hold |
| HSBC FTSE 100 UCITS ETF | HUKX | 0.07% | Distributing | Low-cost alternative |
| iShares MSCI UK ETF (EWU) | EWU | 0.50% | Distributing | US investors (USD-denominated) |
The ongoing charge is the annual fee you pay for holding the fund — expressed as a percentage of your investment. At 0.07%, iShares and HSBC are the cheapest. On a £10,000 investment, that’s just £7 per year in fund fees.
Step 4: Decide Between Distributing and Accumulating
Most FTSE 100 ETFs come in two flavours: distributing (dividends are paid out to you as cash) and accumulating (dividends are automatically reinvested into the fund). If you’re in a growth phase and don’t need income immediately, accumulating units are generally the more efficient choice for long-term compounding.
Step 5: Invest and Stay the Course
Once you’ve chosen your ETF, deposit money into your account via bank transfer and place a buy order. Many platforms allow you to set up automatic regular investments from as little as £20 per month — a strategy that helps you benefit from pound-cost averaging over time.
For US Investors
If you’re based in the United States, buying a UK-listed UCITS ETF directly can be complicated due to PRIIP (Packaged Retail Investment and Insurance Products) regulations that restrict the sale of EU/UK-domiciled funds to US retail investors. But there are straightforward workarounds.
Option 1: iShares MSCI UK ETF (Ticker: EWU)
EWU is listed on the NYSE Arca and is managed by BlackRock. It tracks the MSCI UK Index, which closely mirrors the FTSE 100 composition, covering over 85% of the UK stock market by value. It is denominated in US dollars and available through any major US brokerage — Fidelity, Charles Schwab, TD Ameritrade, or Robinhood — with no special requirements. The expense ratio is 0.50% per year.
Option 2: Open an International Brokerage Account
Platforms such as Interactive Brokers allow US-resident investors to access London Stock Exchange-listed ETFs directly. This gives you access to cheaper UCITS ETFs like the iShares Core FTSE 100 UCITS ETF (ISF) with its 0.07% expense ratio, though currency conversion costs apply.
Option 3: Broader UK/Europe Exposure
US investors seeking European diversification sometimes use funds like the Vanguard FTSE Europe ETF (VGK), which includes significant UK exposure alongside France, Germany, Switzerland, and other European markets. The expense ratio is just 0.06%.
What Are the Risks of Investing in the FTSE 100?
No investment is risk-free, and the FTSE 100 is no exception. Here are the key risks to keep in mind:
- Market risk: The FTSE 100 fell sharply during the 2008 financial crisis and the 2020 pandemic. Investments can and do go down.
- Concentration risk: The top 10 FTSE 100 companies account for roughly 40% of the index’s total value. Problems in financials or energy can disproportionately affect the whole index.
- Currency risk: For US investors holding sterling-denominated assets, fluctuations in the GBP/USD exchange rate will impact your actual returns in dollars.
- Sector bias: The FTSE 100’s limited technology exposure means it can underperform during tech-driven bull markets (as it did relative to the S&P 500 during the 2010s).
- Dividend variability: Dividends are never guaranteed. Companies can cut or cancel payments during economic downturns.
“The FTSE 100 is best suited for long-term investors with a time horizon of at least five years. Short-term volatility is normal; patient investors have historically been rewarded.”
How Has the FTSE 100 Performed?
The FTSE 100 has delivered strong performance over the past two years. In 2025, the index rose approximately 20%, and over the two-year period to early 2026 it is up over 35%. On 27 February 2026, the index reached an all-time closing high of 10,910.55.
However, it’s important to use total return figures — including reinvested dividends — when assessing long-term performance. The price return of the FTSE 100 alone understates investor experience significantly. Over four decades, the total return index has doubled almost five times, while the price-only index has approximately doubled three times over the same period.
Compared to the S&P 500, the FTSE 100 has historically lagged on pure capital growth, but has often outperformed on income. Its valuation is also generally considered more conservative — trading at lower price-to-earnings multiples than US equivalents, which makes it attractive to value-focused investors.
FTSE 100 vs. FTSE 250 vs. FTSE All-Share: What’s the Difference?
It’s easy to confuse the various FTSE indices. Here’s a quick breakdown:
- FTSE 100 — The top 100 UK companies by market cap. Heavily weighted toward global multinationals. Represents ~80% of total UK market value.
- FTSE 250 — The next 250 companies after the top 100. More domestically focused and considered a better barometer of the UK economy itself. Represents ~15% of market value.
- FTSE All-Share — Combines the FTSE 100, FTSE 250, and FTSE Small Cap indices, covering 98-99% of the UK market. Considered the most comprehensive measure of UK equity market performance.
For most beginners, the FTSE 100 is the natural starting point — it’s the most liquid, the most widely tracked, and has the most ETF options available with the lowest costs.
Final Thoughts: Is the FTSE 100 Right for You?
If you’re looking for a straightforward, low-cost way to invest in large, established businesses with a strong income track record, the FTSE 100 is one of the best places to start.
For UK investors, wrapping your FTSE 100 ETF inside a Stocks and Shares ISA gives you a tax-efficient home for long-term wealth building. Set up a monthly direct debit, choose an accumulating ETF, and let compounding do its work over the years.
For US investors, EWU provides accessible USD-denominated exposure to the UK’s blue-chip index through any major American brokerage.
The FTSE 100 won’t make you rich overnight — but that’s never been its purpose. It’s a wealth-building engine for patient investors who understand that time in the market, not timing the market, is the real edge.
FREQUENTLY ASKED QUESTIONS
What Is the FTSE 100? 10 Common Questions Answered
1. What does FTSE 100 stand for?
FTSE stands for Financial Times Stock Exchange — a name that reflects the two organisations that originally collaborated to create the index: the Financial Times newspaper and the London Stock Exchange. The “100” refers to the number of companies tracked. The index was launched on 3 January 1984 with a starting value of 1,000 points. Today it is managed by FTSE Russell, a subsidiary of the London Stock Exchange Group (LSEG).
2. Can you invest directly in the FTSE 100 index itself?
No — the FTSE 100 is not a company or a fund you can buy shares in directly. It is a measurement, similar to a temperature reading. What you can do is invest in financial products that are designed to replicate the performance of the index. The most common and cost-effective options are Exchange-Traded Funds (ETFs) and index tracker funds. These hold shares in all 100 constituent companies in the same proportions as the index, so when the FTSE 100 rises, your fund rises too, and vice versa.
3. How often is the FTSE 100 updated?
There are two levels of updates. First, the index level itself is recalculated every 15 seconds during London Stock Exchange trading hours (8:00 AM to 4:30 PM GMT, Monday to Friday). This gives investors a real-time snapshot of how the 100 companies are performing collectively. Second, the composition of the index — meaning which companies are actually included — is reviewed and potentially changed every quarter by FTSE Russell. Companies that rise above or fall below the market capitalisation threshold are promoted or demoted accordingly.
4. What is the difference between the FTSE 100 and the S&P 500?
Both are market-capitalisation-weighted indices tracking the largest listed companies in their respective countries, but they differ significantly in composition. The S&P 500 tracks the 500 largest US companies and is heavily weighted toward technology — Apple, Microsoft, Nvidia, and Amazon together represent a substantial portion. The FTSE 100 tracks 100 UK-listed companies and leans toward financials, energy, healthcare, and consumer staples, with minimal technology exposure. The S&P 500 has historically delivered higher capital growth; the FTSE 100 has historically offered higher dividend yields and trades at lower valuations.
5. Does the FTSE 100 pay dividends?
The index itself does not pay dividends — it is simply a measure of stock prices. However, the majority of companies within the FTSE 100 do pay regular dividends to their shareholders. When you hold a FTSE 100 ETF or index fund, you benefit from those dividends either as cash payments (in a distributing fund) or as automatic reinvestment into additional fund units (in an accumulating fund). The FTSE 100 has a reputation as a strong income index: analysts forecast record total dividend payments of approximately £88 billion across the index’s constituent companies in 2026, with the index’s forward yield sitting around 3.3%.
6. How much money do I need to start investing in the FTSE 100?
For most beginners, a FTSE 100 index fund or ETF represents one of the most sensible ways to start investing. It provides instant diversification across 100 major companies, charges very low annual fees (as little as 0.07% for the cheapest ETFs), requires no active decision-making about individual stocks, and is simple to understand. The main caveat is that it should form part of a broader diversified portfolio over time, ideally including exposure to US and global markets as well, since the FTSE 100 is relatively light on technology and may underperform US-heavy indices during tech-led bull markets.
8. What is the FTSE 100’s all-time high?
As of the time of writing in May 2026, the FTSE 100’s all-time closing high was 10,910.55, reached on 27 February 2026. The highest intraday value was 10,934.94, also recorded on that same date. To put that in perspective, the index started at 1,000 points in January 1984, meaning it has grown more than tenfold on a price basis over four decades. When total returns including reinvested dividends are factored in, the growth is considerably higher.
9. How do US investors buy the FTSE 100?
US-based investors cannot easily purchase UK-domiciled UCITS ETFs directly due to regulatory restrictions, but there are accessible alternatives. The iShares MSCI UK ETF (ticker: EWU), listed on NYSE Arca and available through any major US brokerage, provides broad exposure to large UK companies including the majority of FTSE 100 constituents. It is USD-denominated and carries an expense ratio of 0.50%. Investors willing to open an international brokerage account through a provider like Interactive Brokers can also access London-listed ETFs directly, at much lower expense ratios of around 0.07%.
10. What are the tax implications of investing in the FTSE 100 in the UK?
For UK investors, the account type you use determines your tax treatment. Within a Stocks and Shares ISA, all investment gains and dividend income are completely sheltered from capital gains tax and income tax, and you can invest up to £20,000 per tax year. Within a SIPP, contributions receive government tax relief (meaning a basic-rate taxpayer gets a 25% top-up on contributions), and growth is tax-free, though withdrawals in retirement are subject to income tax. A General Investment Account (GIA) offers no tax shelter, so gains above the annual CGT allowance and dividends above the dividend allowance will be taxable. Tax rules can change and depend on individual circumstances; consulting a qualified financial adviser is always recommended for personalised guidance.
Disclaimer: This article is for educational and informational purposes only and does not constitute financial advice. Investments can go up and down in value, and you may get back less than you invest. Past performance is not a reliable indicator of future results. Always do your own research and consider seeking independent financial advice before making investment decisions. Tax treatment depends on individual circumstances and may be subject to change.