The FTSE indices are a family of benchmarks that track the performance of companies listed on the London Stock Exchange. From the largest blue-chip firms to smaller growth businesses, they give investors a clear view of different segments of the UK market.
What Does FTSE Mean
FTSE stands for Financial Times Stock Exchange. The name comes from the Financial Times and the London Stock Exchange, which together launched the first FTSE index.
Today, the indices are maintained by FTSE Russell↗︎, a subsidiary of the London Stock Exchange Group, also known as LSEG.
The FTSE 100
Launched on 3 January 1984 with a base value of 1,000 points (reaching 10,989.45 in 2026), the FTSE 100 tracks the 100 largest companies on the London Stock Exchange by market value. Known as the “Footsie”, it is one of the most widely followed indices in the UK market.
The index is weighted by market capitalisation, meaning larger companies have a greater influence on its performance. Shell and Unilever, for example, together account for nearly 10% of the index. Its constituents include global names such as AstraZeneca, HSBC, BP, GSK, Rio Tinto, RELX, Diageo and Glencore, many of which operate internationally.
For investors, a rising FTSE 100 signals confidence and a healthy market, while a falling index can indicate economic or geopolitical concerns and weaker investor sentiment. The index is reviewed quarterly, with companies added or removed based on market value.
The FTSE 250
Created in 1992 with a base level of 2,403 (reaching 25,134.77 in 2026), the FTSE 250 tracks the 250 largest companies after the FTSE 100. These firms tend to be more UK-focused, making the index a key indicator of domestic business conditions.
Its members include well-known companies such as easyJet, Dr Martens, Greggs, Rightmove and Ocado. The index is reviewed quarterly, with companies promoted to or relegated from the list based on market value.
The FTSE 350
The FTSE 350 combines the FTSE 100 and FTSE 250 to cover the 350 largest companies on the London Stock Exchange. Launched in 1983, it is weighted by market capitalisation and reviewed four times a year. It provides a snapshot of the largest businesses across both the blue-chip and mid-cap sectors.
The FTSE Small Cap
The FTSE Small Cap covers companies ranked from around 351st to 619th by market value on the London Stock Exchange’s main market. Launched in 2004, the index gives investors a way to track smaller listed businesses that sit below the FTSE 350. Its constituents are weighted by market capitalisation, with regular reviews allowing companies to move in or out as their market value changes.
Well-known constituents have included AO World, B&M European Value Retail, Pets at Home, Trainline and WH Smith.
The FTSE All-Share
The FTSE All-Share combines the FTSE 100, FTSE 250 and FTSE SmallCap, covering around 98% of the UK market’s capitalisation. Launched in 1962 as the FTSE Actuaries All Share Index, it is the main measure of the overall performance on the London Stock Exchange’s main market.
The FTSE AIM
The Alternative Investment Market (AIM) was launched in 1995 as a more flexible market for smaller and growing companies, replacing the Unlisted Securities Market.
AIM-listed businesses face lighter regulations than those in the main market, which has made them attractive to both UK and international businesses.
FTSE Russell also maintains several other AIM indices, including the FTSE AIM 50, FTSE AIM 100 and FTSE AIM All-Share.
AIM constituents have included Jet2, YouGov, GlobalData and Hutchmed.
Putting it Together
Each FTSE index serves a different purpose, with the FTSE 100 tracking the largest companies with global reach, the FTSE 250 covering mid-sized firms with greater exposure to the UK economy, and the FTSE 350 combining both to provide a broader view of the market.
The FTSE Small Cap and AIM indices track smaller companies, with the AIM tracking early-stage and growth businesses. The FTSE All-Share brings together the main AIM market in its entirety.
The FTSE Russell
FTSE Russell is a subsidiary of the London Stock Exchange Group (LSEG) and the Financial Times Stock Exchange (FTSE).
It designs, calculates and manages indices across equities, fixed income and commodities. Its benchmarks are used globally by investors and financial institutions to track performance, construct portfolios and develop products such as ETFs and derivatives.
FTSE Russell manages a large number of indexes across different asset classes and key global regions. The key indexes it oversees include:
UK and European Indexes:
- FTSE 100 Index
- FTSE 250 Index
- FTSE 350 Index
- FTSE SmallCap Index
- FTSE All-Share Index
- FTSE AIM UK 50 Index
- FTSE AIM 100 Index
- FTSE AIM All-Share Index
- FTSE MIB (Italy)
Russell Indexes (US Market):
- Russell 3000 Index
- Russell 2500 Index
- Russell 2000 Index (widely tracked US small-cap index)
- Russell 1000 Index
- Russell Top 200 Index
- Russell Top 50 Index
- Russell Midcap Index
- Russell Microcap Index
- Russell Small Cap Completeness Index
Global Equity Indexes:
- FTSE Global Equity Index Series
- FTSE4Good Index (focused on sustainable and ethical investments)
Frequently Asked Questions
Still have questions about FTSE indices? Here are some quick answers to the most common ones.
Can I Invest Directly In The FTSE 100?
You can’t buy the FTSE 100 directly, but you can invest in its performance:
Individual Stocks: Buy shares of FTSE 100 companies directly.
ETFs: Hold a small slice of all 100 companies to track the index.
CFDs & Spread Betting: Speculate on price movements, high risk.
Futures: Contracts to buy or sell the index at a set date, high risk.
Does the FTSE 100 include international companies?
Yes, the FTSE 100 includes international companies. The London Stock Exchange doesn’t restrict membership based on a company’s headquarters or primary operations. This means some of the largest companies in the FTSE 100 might be multinational corporations with significant business conducted outside the UK
How often do FTSE 100 companies change?
The FTSE 100 companies are reviewed and can potentially change every quarter. This means companies are assessed regularly, and the index composition can be adjusted in March, June, September, and December.
