The FTSE 100 represents the performance of blue-chip companies across various sectors, including financials, energy, healthcare, and consumer goods, among others. It is one of the most widely followed indices in the world and is considered a benchmark for the UK stock market.

The index is calculated based on the market capitalization of the constituent companies, which is determined by multiplying the number of shares outstanding by the current stock price. The index is adjusted periodically to reflect changes in the market capitalization of the constituent companies.