The FTSE 250 Index, also called the FTSE 250, or, informally, the "Footsie 250", is a stock market index that measures the real strength of the economy of the United Kingdom and consists of the 101st to the 350th mid-cap blue chip companies listed on the London Stock Exchange. The index consists of 38 sectors, three of which have a market cap exceeding £25 billion as at 28 June 2024. These are collective investments, investment banking & investment services, and residential and commercial REIT, which together account for approximately 56% of the index's market cap. At the same date there was one company with a market cap exceeding £4 billion: Polar Capital, which accounts for approximately 1% of the market cap. Each calendar quarter, the FTSE 250's constituents are reviewed and some companies will either exit or enter the index, resulting in irregular trading volume and price changes as market participants rebalance their portfolios. Related indices are the FTSE 100 Index, the FTSE 350 Index, the FTSE SmallCap Index and the FTSE All-Share Index. Wikipedia