About

The FTSE 100 Index, also called FTSE 100, FTSE, or, informally, the “footsie”, is a share index of the 100 companies listed on the London Stock Exchange with the highest market capitalization. It is one of the most widely used stock indices and is seen as a gauge of business prosperity for business regulated by UK company law. The index is maintained by the FTSE Group, a subsidiary of the London Stock Exchange Group.

The index began on 3 January 1984 at the base level of 1000; the highest value reached to date is 6950.6, on 30 December 1999. After falling during the financial crisis of 2007-2010 to below 3500 in March 2009, the index recovered to a peak of 6091.33 on 8 February 2011, fell under the 5000 mark on the morning of 23 September 2011, but reached 6,840.27 (its highest since September 2000) on 22 May 2013.

The index is maintained by the FTSE Group, a now wholly-owned subsidiary of the London Stock Exchange which originated as a joint venture between the Financial Times and the London Stock Exchange. It is calculated in real time and published every 15 seconds.

FTSE 100 companies represent about 81% of the entire market capitalisation of the London Stock Exchange. Even though the FTSE All-Share Index is more comprehensive, the FTSE 100 is by far the most widely used UK stock market indicator. Other related indices are the FTSE 250 Index (which includes the next largest 250 companies after the FTSE 100), the FTSE 350 Index (which is the aggregation of the FTSE 100 and 250), FTSE SmallCap Index and FTSE Fledgling Index. The FTSE All-Share aggregates the FTSE 100, FTSE 250 and FTSE SmallCap.

The constituents of the index are determined quarterly; the largest companies in the FTSE 250 Index are promoted if their market capitalisation would place them in the top ninety companies of the FTSE 100 Index.

Component companies must meet a number of requirements set out by the FTSE Group, including having a full listing on the London Stock Exchange with a Sterling or Euro denominated price on the Stock Exchange Electronic Trading Service, and meeting certain tests on nationality, free float, and liquidity.

Continuous trading on the London Stock Exchange starts at 08:00 and ends at 16:30 (when the closing auction starts), and closing values are taken at 16:35.