FTSE 100 Index — BrandWiki

FTSE 100 Index

Overview

FTSE 100

class	skin-invert
foundation	3 January 1984
operator	FTSE Russell
symbol	UKX
exchanges	London Stock Exchange
constituents	100 (March 2026)
cap level	Large-cap
mcap	trillion (March 2026)
weighting	Capitalisation-weighted
related	FTSE 250 Index FTSE 350 Index FTSE SmallCap Index FTSE All-Share Index FTSE Fledgling Index FTSE AIM UK 50 Index
homepage	https://www.lseg.com/en/ftse-russell/indices/uk
reuters	.FTSE
bloomberg	UKX:IND

The Financial Times Stock Exchange 100 Index, also called the FTSE 100 Index, FTSE 100, FTSE or, informally, the "Footsie", is one of the United Kingdom's best-known stock market indices and represents the 100 most highly capitalised blue chips listed on the London Stock Exchange.[1]

History

The index started on 3 January 1984,[2][3] having been constructed by the London Stock Exchange to better reflect activity on the market. The index would replace the Financial Times' own FT 30 after its public unveiling on 14 February.[4][5]

Description

The index has trading symbol UKX[1] and is maintained by FTSE Russell, a wholly owned subsidiary of London Stock Exchange Group, which originated as a joint venture between the Financial Times and the London Stock Exchange. It is calculated in real time and published every second when the market is open.[2]

The FTSE 100 broadly consists of the largest 100 qualifying UK companies by full market value.[23] The total market value of a company is calculated by multiplying the share price of the company by the total number of shares they have issued.[24] The index therefore only reacts to a change in the market value of the companies excluding any dividend income an investor may otherwise reinvest. In order to view the effect of both market value performance and income relative to the FTSE 100 Index alone the FTSE 100 Total Return Index is used. Over the last four decades the total return index has doubled almost five times whilst the index has doubled slightly more than three times respectively.[25] Further, many of these are internationally focused companies: therefore the index's movements are a fairly weak indicator of how the UK economy is faring and are significantly affected by the exchange rates of the pound sterling.[26] A better indication of the UK economy is the FTSE 250 Index, as it contains a smaller proportion of international companies.[27]

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 the FTSE Fledgling Index. The FTSE All-Share aggregates the FTSE 100, FTSE 250 and FTSE SmallCap.[1]

The index consists of 18 ICB Supersectors, four of which had a market capitalisation exceeding £250 billion as of 31 March 2026. These are Banks, Health Care, Industrial Goods and Services and Energy, which together account for approximately 54% of the index's capitalisation. On the same date, there were three companies with a market cap exceeding £200 billion: AstraZeneca, HSBC and Shell, which together accounted for approximately 26% of the market cap.[28]

Each calendar quarter, the FTSE's constituents are reviewed and some companies exit or enter the index, resulting in irregular trading volume and price changes as market participants rebalance their portfolios.[3]

Weighting

In the FTSE indices, share prices are weighted by free-float capitalisation, so that the larger companies, with more of their stock "floating", make more of a difference to the index than smaller companies. The basic formula for these indices is:[29]

expanded to,

where the sum of the products of the price, shares, and FFF for each component beginning at i=1 through to, usually, n=100 at time t are divided by the to give the index~value.

The free float factor represents the percentage of all issued shares that are readily available for trading, rounded up to the nearest multiple of 5%. The free-float capitalisation of a company is its market capitalisation multiplied by its free float adjustment factor. It therefore does not include restricted stocks, such as those held by company insiders.[29]

It follows that the at any chosen time, when there are no changes, is derived by rearranging the basic formula to give:

However, as with any price index the FTSE 100 Index is always changing, whether by corporate action or constituent change. In order to maintain a true reflection of market price movements the is adjusted to mitigate any effect these changes have on the index value.

Past constituents

All changes are due to market capitalisation changes unless noted otherwise. • Abrdn

• Abbey Life (became subsidiary of Lloyds TSB in 1996, then sold to Deutsche Bank in 2007)[40]

• Abbey National (acquired by Banco Santander Central Hispano, now part of its Santander UK subsidiary)[41]

• Aberdeen Asset Management

• African Barrick Gold

• Aggreko

• Alliance & Leicester (acquired by Banco Santander Central Hispano, now part of its Santander UK subsidiary)[42]

• Alliance Boots (acquired by private equity fund controlled by Kohlberg Kravis Roberts)[43]

• Alliance Trust

• Allied Domecq (acquired by Pernod Ricard)[44]

• Allied Zurich (dual holding company along with Zurich Allied, companies unified in 2000 to form Zurich Financial Services)[45]

• Amec

• Amersham (acquired by GE, now part of its GE Healthcare division)[46]

• Amstrad (acquired by British Sky Broadcasting)[47]

• Argos (acquired by GUS)[48]

• Argyll Group (renamed Safeway in 1996, then taken over by Morrisons in 2004)[49]

• Arjo Wiggins Appleton (acquired by Worms & Cie)[50]

• ARM Holdings (acquired by SoftBank Group)[51]

• ASDA Group (acquired by Wal-Mart)[52]

• Ashtead Group (transfer of listing to the US)[53]

• Avast (acquired by NortonLifeLock)[54]

• Aveva (acquired by Schneider Electric)[55]

• BAA (acquired by Ferrovial)[56]

• Balfour Beatty

• Baltimore Technologies (acquired by Oryx International Growth Fund)[57]

• Bank of Scotland (merged with Halifax to form HBOS, now part of the Lloyds Banking Group)[58]

• Bass (became Six Continents and then InterContinental Hotels Group)[59]

• Beecham Group (merged with SmithKline and then with Glaxo to become GlaxoSmithKline)[60]

• Berisford (renamed Enodis, subsequently acquired by The Manitowoc Company)[61]

• BET, formerly British Electric Traction (acquired by Rentokil)[62]

• BG Group (acquired by Royal Dutch Shell)[63]

• BHP (moved main stock listing to the Australian Securities Exchange)[64]

• BICC (renamed Balfour Beatty)[65]

• British Land

• Blue Arrow (acquired by Corporate Services Group)[66]

• Blue Circle Industries (acquired by Lafarge)[67]

• BOC (acquired by Linde)[68]

• Bowater (renamed Rexam)[69]

• Bookham Technology (renamed Oclaro and now traded on Nasdaq)[70]

• B&M

• BPB Industries (acquired by Saint-Gobain)[71]

• Bradford & Bingley (branch network acquired by Banco Santander Central Hispano, now part of its Santander UK subsidiary; loans book nationalised)[72]

• Brambles Industries (now only listed on the Australian Securities Exchange)[73]

• British Aerospace (merged with Marconi Electronic Systems to form BAE Systems)[74]

• British Airways (merged with Iberia to form International Airlines Group)[75]

• British Home Stores (acquired by Storehouse and then sold to Philip Green)[76][77]

• British Steel (merged with Koninklijke Hoogovens to become Corus Group, now Tata Steel Europe)[78]

• British & Commonwealth (collapsed in 1990)[79]

• Britoil (acquired by BP)[80]

• BTR (merged with Siebe to form BTR Siebe, subsequently renamed Invensys)[81]

• Burmah Oil (renamed Burmah Castrol and acquired by BP)[82]

• Burton Group (renamed Arcadia and acquired by Philip Green)[83]

• Cable & Wireless Worldwide (acquired by Vodafone)[84]

• Cadbury (acquired by Kraft Foods)[85]

• Cairn Energy

• Capita

• Carlton Communications (merged with Granada to form ITV)[86]

• Carnival Corporation & plc

• Carphone Warehouse

• Celltech (acquired by UCB in 2004)[87]

• CMG (merged with Logica to form LogicaCMG)[88]

• Coats Viyella (acquired by Guinness Peat Group and renamed Coats)[89]

• Cobham

• Colt Group

• Commercial Union Assurance (merged with General Accident to form CGU, itself now part of Aviva)[90]

• Consolidated Gold Fields (acquired by Hanson)[91]

• Cookson Group

• Corus Group (acquired by Tata Steel, now forming its Tata Steel Europe division)[78]

• Courtaulds (demerged into two businesses acquired by Sara Lee and Akzo Nobel)[92]

• CRH moved primary listing to New York[93]

• Daily Mail and General Trust

• Dalgety (renamed PIC International and then Sygen International and subsequently acquired by Genus)[94]

• Darktrace (acquired by Thoma Bravo)[95]

• Debenhams

• Dechra Pharmaceuticals (acquired by EQT AB)[96]

• De La Rue

• Dimension Data Holdings (market capitalisation fell too low, subsequently acquired by Nippon Telegraph and Telephone)[97]

• Direct Line Group

• Distillers (acquired by Guinness and now part of Diageo)[98]

• Dixons Carphone

• Dixons Group (renamed to DSG International and then Dixons Retail; market capitalisation also fell too low)[99]

• Dowty Group (acquired by TI Group, itself now part of Smiths Group)[100]

• DSG International (renamed Dixons Retail; market capitalisation also fell too low)[99]

• Eagle Star (acquired by BAT Industries and then demerged as part of Zurich Financial Services)[101]

• Eastern Group (acquired by Hanson, renamed The Energy Group; acquired by Texas Utilities)[102]

• EasyJet

• ECC Group (acquired by Imetal)[103]

• Edinburgh Investment Trust

• Electrocomponents

• EMAP (acquired by Apax Partners and the Guardian Media Group)[104]

• EMI Group (acquired by Terra Firma Capital Partners, now owned by Citigroup)[105]

• Energis (acquired by Cable and Wireless)[106]

• Enterprise Inns

• Enterprise Oil (acquired by Royal Dutch Shell)[107]

• Essar Energy

• Eurasian Natural Resources Corporation

• Eurotunnel

• Evraz

• Exco International (acquired by British & Commonwealth Holdings)[108]

• Exel (acquired by Deutsche Post)[109]

• Ferguson (moved main listing to New York Stock Exchange)[110]

• Ferranti International (collapsed in 1993)[111]

• Ferrexpo

• FirstGroup

• Fisons (acquired by Rhone-Poulenc Rorer, now Sanofi-Aventis)[112]

• Flutter Entertainment (moved listing to New York Stock Exchange)[113]

• Forte (acquired by Granada, now ITV)[114]

• Frasers Group

• Freeserve (acquired by France Télécom, now Orange)[115]

• Friends Life (acquired by Aviva)[116]

• Friends Provident (acquired by Friends Life Group)[117]

• G4S

• Gallaher Group (acquired by Japan Tobacco)[118]

• Gateway Corporation (renamed Somerfield, subsequently acquired by The Co-operative Group)[119]

• GEC, formerly General Electric Company (renamed Marconi, broken up, remnant renamed Telent)[120]

• General Accident (merged with Commercial Union to form CGU, itself now part of Aviva)[90]

• George Wimpey (merged with Taylor Woodrow to form Taylor Wimpey)[121]

• Glaxo Wellcome (merged with SmithKline Beecham to form GlaxoSmithKline)[60]

• Globe Investment Trust (acquired by British Coal Pension Fund)[122]

• Granada Compass (split in 2001 to leave Granada and Compass Group)[123]

• Granada (merged with Carlton Communications to form ITV)[86]

• Greenall's Group (renamed De Vere Group and then acquired by a joint venture of private investors)[124]

• Grand Metropolitan (merged with Guinness to form Diageo)[125]

• Guardian Royal Exchange (acquired by Axa)[126]

• Guinness (merged with Grand Metropolitan to form Diageo)[125]

• GUS (now demerged into Home Retail Group and Experian)[127]

• GVC Holdings (changed its name to Entain plc)[128]

• Habitat Mothercare (merged with British Home Stores to form Storehouse and subsequently renamed Mothercare again)[129]

• Halifax Group (merged with the Bank of Scotland to form HBOS)[58]

• Hambro Life (renamed Allied Dunbar and acquired by BAT Industries and then demerged as part of Zurich Financial Services)[130]

• Hammerson

• Hanson (acquired by Heidelberg Cement)[131]

• Harbour Energy

• Hargreaves Lansdown (acquired by CVC Capital Partners, Nordic Capital and the Abu Dhabi Investment Authority)[132]

• Harrisons & Crosfield (renamed Elementis)[133]

• Hawker Siddeley (acquired by BTR, now Invensys)[134]

• Hays

• HBOS Group plc (acquired by Lloyds Banking Group)[135]

• Hikma Pharmaceuticals

• Hillsdown Holdings (acquired by Hicks, Muse, Tate and Furst and then sold on as Premier Foods)[136]

• Home Retail Group

• Homeserve (acquired by Brookfield Asset Management)[137]

• House of Fraser (acquired by Baugur)[138]

• ICAP

• Imperial Chemical Industries (acquired by Akzo Nobel)[139]

• Imperial Continental Gas Association (broke up into Calor and Contibel)[140]

• Inchcape

• Inmarsat

• Innogy Holdings (renamed Npower and acquired by RWE)[141]

• International Power (acquired by GDF Suez)[142]

• Intu

• Invensys

• Invesco (moved primary listing to NYSE)[143]

• Investec

• ITV

• Jaguar (acquired by Ford and then by Tata Motors)[144]

• Johnson Matthey

• Just Eat Takeaway (nationality reassigned to the Netherlands)[145]

• Kazakhmys

• Kelda Group (acquired by Saltaire Water consortium)[146] a consortium of investment companies including Citigroup and HSBC.[147]

• Kingston Communications (renamed KCOM Group and market capitalisation fell too low)[148]

• Kwik Save Group (merged with Somerfield)[149]

• Ladbrokes

• Laporte (major divisions acquired by Kohlberg Kravis Roberts)[150]

• Lasmo (acquired by Eni)[151]

• Lattice Group (merged with National Grid to form National Grid Transco)[152]

• Lever Brothers (merged with Margarine Unie to form Unilever)[153]

• Logica

• London Electricity (acquired by Électricité de France, now part of its EDF Energy division)[154]

• Lonhro (renamed Lonmin)[155]

• Lonmin

• Lucas Industries (merged with Varity to form LucasVarity, then acquired by TRW)[156]

• LucasVarity (acquired by TRW)[156]

• Magnet and Southerns (acquired by Berisford)[157]

• Man Group

• Maxwell Communications Corporation (collapsed in 1991)[158]

• MB-Caradon (renamed Caradon and then Novar, then acquired by Honeywell)[159]

• Mediclinic International

• Meggitt (acquired by Parker Hannifin)[160]

• MEPC (acquired by Leconport Estates)[161]

• Mercury Asset Management (acquired by Merrill Lynch)[162]

• Merlin Entertainments

• MFI (renamed Galiform and then Howden Joinery and market capitalisation fell too low)[163]

• Micro Focus International

• Midlands Electricity (acquired by Acquila Sterling, now part of E.ON Energy UK)[164]

• Midland Bank (acquired by HSBC)[165]

• Misys

• Mitchells & Butlers

• Morrisons (acquired by Clayton, Dubilier & Rice)[166]

• National Westminster Bank (acquired by Royal Bank of Scotland Group)[167]

• NFC (merged with Ocean Group to form Exel, now part of Deutsche Post)[168]

• NMC Health (listing suspended)

• Northern Foods (market capitalisation fell too low, before being acquired by Ranjit Boparan)[169]

• Northern Rock (market capitalisation fell too low, before being nationalised)[170]

• Norwich Union (merged with CGU to form CGNU, now Aviva)[90]

• Nycomed Amersham (acquired by GE)[46]

• O2 (renamed Telefónica Europe following acquisition by Telefónica)[171]

• Ocado

• Old Mutual (managed separation of the business)[172]

• Orange (acquired by Mannesmann and then by France Télécom, now Orange)[173]

• PartyGaming (market capitalisation fell too low, before merging with Bwin to become bwin.party digital entertainment)[174]

• P&O (acquired by Dubai Ports World)[175]

• P&O Princess Cruises (merged with Carnival Corporation and re-listed as Carnival Corporation & plc)[176]

• Pennon Group

• Petrofac

• Pilkington (acquired by Nippon Sheet Glass)[177]

• Plessey (acquired by GEC and Siemens)[178]

• Polly Peck (collapsed in 1990)[179]

• Polymetal International

• PowerGen (acquired by E.ON Energy UK)[180][181]

• Provident Financial

• Psion

• Punch Taverns

• Racal Electronics (acquired by Thomson-CSF and then Thales Group)[182]

• Railtrack (collapsed in 2001)[183]

• Randgold Resources (merged with Barrick Gold Corp)[184]

• Rank Hovis McDougall (acquired by Premier Foods)[185]

• Reckitt & Colman (merged with Benckiser to form Reckitt Benckiser)[186]

• Redland (acquired by Lafarge)[187]

• Reed International (merged with Elsevier to form Reed Elsevier)[188]

• Renishaw

• Rentokil Initial

• Resolution Limited (changed its name to Friends Life Group)[189]

• Resolution plc (acquired by Pearl Group)[190]

• Rexam (acquired by Ball Corporation)[191]

• RMC Group (acquired by Cemex)[192]

• Rothmans International (acquired by British American Tobacco)[193]

• J Rothschild (renamed St. James's Place and market capitalisation fell too low)[194]

• Rowntree's (acquired by Nestlé)[195]

• Royal Insurance (merged with Sun Alliance Group to form Royal & SunAlliance)[196]

• Royal Mail

• RS Group

• RSA Insurance Group (acquired by Danish insurer Tryg and Canada's Intact Financial Corporation in May 2021).[197]

• Saatchi & Saatchi (acquired by Publicis)[198]

• Safeway (acquired by Morrisons)[199]

• SABMiller (acquired by Anheuser-Busch InBev)[200]

• Scottish & Newcastle (acquired by a consortium formed of Heineken & Carlsberg)[201]

• Scottish Hydro Electric (merged with Southern Electric to form Scottish and Southern Energy)[202]

• ScottishPower (acquired by Iberdrola)[203]

• Sears (acquired by January Investments – itself controlled by Philip Green)[204]

• Securicor (merged with Group 4 Falck to form G4S)[205]

• Sedgwick (acquired by Marsh & McLennan)[206]

• Sema Group (acquired by Schlumberger)[207]

• Serco

• Shell Transport and Trading Company (later re-organised with Royal Dutch Petroleum Company as Royal Dutch Shell and then renamed Shell plc)[208]

• Shire (acquired by Takeda Pharmaceutical Company)[209]

• Siebe (merged with BTR to form Invensys)[81]

• Sky (acquired by Comcast)[210]

• SmithKline Beecham (merged with Glaxo Wellcome to form GlaxoSmithKline)[60]

• DS Smith (acquired by International Paper)[211]

• Smiths Industries (renamed to Smiths Group)[212]

• Smurfit Kappa (merged with WestRock to form Smurfit WestRock)[213]

• Southern Electric (merged with Scottish Hydro Electric to form Scottish and Southern Energy)[202]

• Spirent

• Sports Direct

• Stagecoach Group

• Standard Telephones and Cables (renamed STC and acquired by Nortel)[214]

• Storehouse (renamed Mothercare)[215]

• Sun Alliance Group (merged with Royal Insurance to form Royal & Sun Alliance)[196]

• Sun Life Assurance (acquired by Axa)[216]

• Sun Life & Provincial Holdings (acquired by Axa)[216]

• Tarmac (acquired by Anglo American)[217]

• Tate & Lyle

• Taylor Wimpey

• Taylor Woodrow (merged with George Wimpey to form Taylor Wimpey)[121]

• Telewest Communications (merged with NTL to form NTL:Telewest now Virgin Media)[218]

• Thames Water (acquired by RWE and then sold to Macquarie Group)[219]

• The Energy Group (acquired by Texas Utilities)[102]

• Thomas Cook Group

• Thomson Reuters (delisted shares from the London Stock Exchange as it ceased to be a dual-listed company)[220]

• Thorn (acquired by Nomura Group)[221]

• Thorn EMI (renamed EMI Group and then acquired by Terra Firma Capital Partners)[221]

• Thus (market capitalisation fell too low, subsequently acquired by Cable & Wireless Worldwide)[222]

• TI Group (acquired by Smiths Group)[223]

• Tomkins (acquired by Onex Corporation and Canada Pension Plan Investment Board)[224]

• Trafalgar House (acquired by Kværner)[225]

• Travis Perkins

• TSB Group (merged with Lloyds Bank to form Lloyds TSB)[226]

• Trusthouse Forte (acquired by Granada)[114]

• TUI Group

• TUI Travel (merged with its German parent to form the TUI Group)[227][228]

• Tullow Oil

• Ultramar (acquired by Lasmo and now part of Eni)

• Unigate (renamed Uniq, then market capitalisation fell too low)[229]

• United Biscuits (acquired by consortium of financial investors)[230]

• United Business Media

• Unite Group

• Vedanta Resources

• Vistry Group

• Warburg SG (acquired by Swiss Bank Corporation, now part of UBS)[231]

• Wellcome (merged with Glaxo to form Glaxo Wellcome, then with SmithKline Beecham to form GlaxoSmithKline)[60]

• WH Smith

• William Hill

• Williams Holdings (demerged into Kidde and Chubb Fire & Security, both now part of United Technologies)[232]

• Willis Corroon (acquired by Trinity Acquisition on behalf of Kohlberg Kravis Roberts and renamed Willis Group)[233]

• Willis Faber (acquired by Trinity Acquisition on behalf of Kohlberg Kravis Roberts and renamed Willis Coroon and then Willis Group)[233]

• Wood Group

• Worldpay (acquired by Vantiv)[234]

• Woolwich (acquired by Barclays)[235]

• WPP

• Yell Group

• Zeneca (merged with Astra to form AstraZeneca)[236]

Source: "FTSE: FTSE 100 Constituent Changes" (PDF; 57.9 KB)

FTSE 100 Index

History

Description

Weighting

Record values

Annual returns

Constituents

Past constituents

FT 30

See also

External links

References

Futures contracts