The FTSE 100 (Financial Times Stock Exchange 100 Index) is the benchmark index for the UK equity market. It tracks the 100 largest companies on the London Stock Exchange by market capitalisation.
The FTSE 100 is capitalisation-weighted, so larger companies move it more. It spans sectors such as financial services, energy, healthcare, consumer goods, mining, and telecommunications.
Traders and investors read the FTSE 100 for UK blue-chip performance. It is the best-known index in the FTSE Russell family, which also runs the FTSE 250 and FTSE All-Share. You can take exposure through index funds, exchange-traded funds, futures, options, or CFDs linked to it.
You follow the FTSE 100 for UK market sentiment.
If heavyweights such as HSBC, Shell, AstraZeneca, and Unilever rise together, the index moves higher. If large banking, energy, or healthcare names fall, it declines, because bigger companies carry more weight in a capitalisation-weighted index.