| 1 | Tokyo Electric Power Company Holdings, Incorporated | Unitedkingdom | Ealing | 13 Elers Road | London | W13 9QA | N/A | 1998 | $57,179,518,290 | 1 | N/A | N/A | N/A |
| 2 | Ed.zublin AG - UK Branch | Unitedkingdom | London | 3rd Floor | London | SW1E 6AS | N/A | 2014 | $17,443,504,496 | 74,340 | N/A | N/A | N/A |
| 3 | Kingfisher PLC | Unitedkingdom | Paddington | 1 Paddington Square | London | W2 1GG | kingfisher.***** | 1982 | $16,073,399,904 | 74,000 | N/A | N/A | N/A |
| 4 | Obayashi CORPORATION | Unitedkingdom | Moorgate | Ground Floor Bracken House | London | EC4M 9JA | obayashi.***** | 1987 | $15,356,732,000 | 6 | N/A | N/A | N/A |
| 5 | Network Rail Infrastructure LIMITED | Unitedkingdom | London | Waterloo General Office | London | SE1 8SW | networkrail.***** | 1994 | $14,318,365,215 | 41,331 | N/A | N/A | N/A |
| 6 | Ge Vernova International LLC | Unitedkingdom | Stafford | C/o UK Grid Solutions Limited | Staffordshire | ST16 1WT | N/A | 1961 | $6,262,662,000 | 421 | N/A | N/A | N/A |
| 7 | Balfour Beatty Group LIMITED | Unitedkingdom | Canary Wharf | 5 Churchill Place | London | E14 5HU | bbcl.***** | 1909 | $5,434,552,734 | 410 | N/A | N/A | N/A |
| 8 | Barratt Redrow PLC | Unitedkingdom | Coalville | Barratt House, Cartwright Way | Leicestershire | LE67 1UF | barrattdevelopments.***** | 1953 | $5,300,649,922 | 6,451 | N/A | N/A | N/A |
| 9 | Bdw Trading LIMITED | Unitedkingdom | Artington | Southern Counties, Compton House, the Guildway | Surrey | GU3 1LR | barratthome.***** | 1995 | $5,241,768,224 | 5,555 | N/A | N/A | N/A |
| 10 | Taylor Wimpey UK LIMITED | Unitedkingdom | Hedsor | Gate House | Buckinghamshire | HP12 3NR | taylorwimpey.***** | 1978 | $4,044,285,885 | 4,354 | N/A | N/A | N/A |
| 11 | Hyosung Heavy Industries CORPORATION | Unitedkingdom | New Malden | 15th Floor C I Tower | London | KT3 4TE | hyosungheavyindustries.***** | 2018 | $3,294,237,771 | 5 | N/A | N/A | N/A |
| 12 | Fcc Construccion S A, UK Branch Office | Unitedkingdom | Ladbroke Grove | 239 Kensington High Street | London | W8 6SN | fcc.***** | 2013 | $3,198,909,882 | 6,946 | N/A | N/A | N/A |
| 13 | Bellway Homes LIMITED | Unitedkingdom | Throckley | Woolsington House | Newcastle Upon Tyne, Tyne and Wear | NE13 8BF | bellway.***** | 1946 | $3,014,241,270 | 2,762 | N/A | N/A | N/A |
| 14 | Ferrovial Agroman International PLC | Unitedkingdom | Chiswick | 10th Floor Bsi Building | London | W4 4AL | ferrovial.***** | 2015 | $2,945,002,701 | 10,416 | N/A | N/A | N/A |
| 15 | Wates Construction LIMITED | Unitedkingdom | Leatherhead | Wates House | Surrey | KT22 7SW | wates.***** | 1986 | $2,845,245,062 | 4,732 | N/A | N/A | N/A |
| 16 | Howden Joinery LIMITED | Unitedkingdom | Chelveston | Raunds 2 | Northamptonshire | NN9 6RJ | howdens.***** | 1995 | $2,822,695,398 | 11,666 | N/A | N/A | N/A |
| 17 | Laing O'rourke PLC. | Unitedkingdom | Longfield | Bridge Place, Anchor Boulevard | Kent | DA2 6SN | laingorourke.***** | 2001 | $2,737,807,036 | 6,363 | N/A | N/A | N/A |
| 18 | Laing O'rourke Holdings LIMITED | Unitedkingdom | Longfield | Bridge Place | Kent | DA2 6SN | laingorourke.***** | 2001 | $2,735,783,060 | 6,363 | N/A | N/A | N/A |
| 19 | Longstaff And Shaw (heating) LIMITED | Unitedkingdom | Croydon | 602 Purley Way | London | CR0 4RF | N/A | 1968 | $2,676,912,418 | 69 | N/A | N/A | N/A |
| 20 | Bloor Holdings LIMITED | Unitedkingdom | Sheepy Magna | Ashby Road | Leicestershire | DE12 7JP | bloorhomes.***** | 1986 | $2,647,791,758 | 4,254 | N/A | N/A | N/A |
| 21 | Laing O'rourke Delivery LIMITED | Unitedkingdom | Longfield | Bridge Place | Kent | DA2 6SN | laingorourke.***** | 1978 | $2,597,518,673 | 800 | N/A | N/A | N/A |
| 22 | Morgan Sindall Construction & Infrastructure LTD | Unitedkingdom | Marylebone | Kent House | London | W1W 8AJ | morgansindall.***** | 1926 | $2,448,755,966 | 3,579 | N/A | N/A | N/A |
| 23 | Galliford Try Holdings PLC | Unitedkingdom | Uxbridge | Blake House | London | UB8 2AD | gallifordtry.***** | 2019 | $2,254,448,486 | 4,122 | N/A | N/A | N/A |
| 24 | Wurttembergische Versicherung Aktiengesellschaft | Unitedkingdom | Moorgate | 21 Lime Street | London | EC3M 7HB | N/A | 1993 | $2,182,097,543 | 3,254 | N/A | N/A | N/A |
| 25 | Redrow LIMITED | Unitedkingdom | Deeside Industrial Park | Redrow House | Flintshire | CH5 3RX | redrow.***** | 1993 | $2,080,481,568 | 1,983 | N/A | N/A | N/A |
| 26 | Redrow Homes LIMITED | Unitedkingdom | Deeside Industrial Park | Redrow House | Flintshire | CH5 3RX | redrow.***** | 1986 | $2,080,481,568 | 1,973 | N/A | N/A | N/A |
| 27 | Kier Construction LIMITED | Unitedkingdom | Cadishead | 2nd Floor Optimum House | Manchester, Greater Manchester | M50 3XP | kier.***** | 1987 | $2,013,653,092 | 2,269 | N/A | N/A | N/A |
| 28 | Galliford Try Construction LIMITED | Unitedkingdom | Uxbridge | Blake House | London | UB8 2AD | gallifordtry.***** | 1977 | $1,827,378,777 | 1,296 | N/A | N/A | N/A |
| 29 | Siemens Gamesa Renewable Energy LIMITED | Unitedkingdom | Bransholme | Sir William Siemens Way | City of Kingston-upon-hull | HU9 1TA | siemensgamesa.***** | 2016 | $1,729,054,798 | 2,775 | N/A | N/A | N/A |
| 30 | Vinci Construction UK LIMITED | Unitedkingdom | Watford | Astral House | Hertfordshire | WD24 4WW | vinciconstruction.***** | 1988 | $1,694,211,356 | 2,821 | N/A | N/A | N/A |
| 31 | Bowmer And Kirkland LIMITED | Unitedkingdom | Belper | High Edge Court | Derbyshire | DE56 2BW | bandk.***** | 1923 | $1,661,703,435 | 1,962 | N/A | N/A | N/A |
| 32 | Skanska UK PLC | Unitedkingdom | Rickmansworth | Maple Cross House | Hertfordshire | WD3 9SW | skanska.***** | 1963 | $1,610,034,736 | 3,239 | N/A | N/A | N/A |
| 33 | Scotia Gas Networks LIMITED | Unitedkingdom | Horley | St Lawrence House | Surrey | RH6 9HJ | sgn.***** | 2003 | $1,603,494,986 | 4,865 | N/A | N/A | N/A |
| 34 | J. Murphy & Sons LIMITED | Unitedkingdom | Kentish Town | Highview House | London | NW5 1TN | murphygroup.***** | 1951 | $1,594,795,931 | 4,060 | N/A | N/A | N/A |
| 35 | Bloor Homes LIMITED | Unitedkingdom | Sheepy Magna | J S Bloor Ltd | Leicestershire | DE12 7JP | bloorhomes.***** | 1987 | $1,592,033,837 | 456 | N/A | N/A | N/A |
| 36 | Costain Group PLC | Unitedkingdom | Moorgate | Seventh Floor | London | EC3A 8BE | costain.***** | 1865 | $1,585,996,950 | 3,182 | N/A | N/A | N/A |
| 37 | Cala Group LIMITED | Unitedkingdom | Gorgie | Adam House | City of Edinburgh | EH11 4DU | cala.***** | 1999 | $1,566,558,314 | 1,469 | N/A | N/A | N/A |
| 38 | Cala Group (holdings) LIMITED | Unitedkingdom | Thorpe | Cala House | Surrey | TW18 3AX | cala.***** | 2013 | $1,566,558,314 | 1,469 | N/A | N/A | N/A |
| 39 | Skanska Construction UK LIMITED | Unitedkingdom | Common Wood | 1 Hercules Way | Hertfordshire | WD25 7GS | N/A | 1923 | $1,562,780,622 | 2,927 | N/A | N/A | N/A |
| 40 | Cala Management LIMITED | Unitedkingdom | Gorgie | Adam House | City of Edinburgh | EH11 4DU | cala.***** | 1925 | $1,539,950,937 | 1,295 | N/A | N/A | N/A |
| 41 | Overbury PLC | Unitedkingdom | Marylebone | Kent House | London | W1W 8AJ | overbury.***** | 1965 | $1,470,154,901 | 951 | N/A | N/A | N/A |
| 42 | Willmott Dixon LIMITED | Unitedkingdom | Letchworth | Suite 201, the Spirella Building | Hertfordshire | SG6 4ET | willmottdixon.***** | 1900 | $1,469,996,441 | 1,594 | N/A | N/A | N/A |
| 43 | City Electrical Factors LIMITED | Unitedkingdom | Kenilworth | 141 | Warwickshire | CV8 2SU | cef.***** | 1951 | $1,468,882,461 | 3,487 | N/A | N/A | N/A |
| 44 | Victoria P.L.C. | Unitedkingdom | Kidderminster | Victoria Carpets | Worcestershire | DY10 1JR | victoriacarpets.***** | 1895 | $1,414,379,729 | 5,355 | N/A | N/A | N/A |
| 45 | Willmott Dixon Construction LIMITED | Unitedkingdom | Letchworth | Suite 201 | Hertfordshire | SG6 4ET | willmottdixon.***** | 1900 | $1,283,992,671 | 1,385 | N/A | N/A | N/A |
| 46 | Winvic Group LIMITED | Unitedkingdom | Spinney Hill | Brampton House | Northamptonshire | NN3 6PZ | winvic.***** | 2006 | $1,278,919,090 | 587 | N/A | N/A | N/A |
| 47 | Winvic Construction LIMITED | Unitedkingdom | Spinney Hill | 19 Tenter Road | Northamptonshire | NN3 6PZ | winvic.***** | 2001 | $1,273,793,054 | 570 | N/A | N/A | N/A |
| 48 | Sir Robert Mcalpine LIMITED | Unitedkingdom | Kings Langley | Concept House | Hertfordshire | WD4 8UD | N/A | 1972 | $1,260,547,310 | 1,838 | N/A | N/A | N/A |
| 49 | Mears LIMITED | Unitedkingdom | Great Witcombe | Unit 5220 2nd Floor Valiant Court | Gloucestershire | GL3 4FE | mearsgroup.***** | 1987 | $1,256,321,034 | 3,244 | N/A | N/A | N/A |
| 50 | Miller Homes LIMITED | Unitedkingdom | Shiremoor | 3.2 Silver Fox Way | North Tyneside, Tyne and Wear | NE27 0QJ | millerhomes.***** | 1934 | $1,254,287,541 | 1,148 | N/A | N/A | N/A |
| 51 | Sig Trading LIMITED | Unitedkingdom | Sheffield | Adsetts House | Sheffield, South Yorkshire | S9 1XH | sigplc.***** | 1979 | $1,248,666,770 | 2,464 | N/A | N/A | N/A |
| 52 | John Graham Construction LIMITED | Unitedkingdom | Hillsborough | Ballygowan Road | South Yorkshire | BT26 6HX | graham.***** | 1955 | $1,203,588,953 | 1,586 | N/A | N/A | N/A |
| 53 | Mclaren Construction LIMITED | Unitedkingdom | Canary Wharf | 20 Churchill Place | London | E14 5HJ | mclarengroup.***** | 2001 | $1,171,516,222 | 912 | N/A | N/A | N/A |
| 54 | Bam Construct & Ventures UK LIMITED | Unitedkingdom | Potten End | Breakspear Park | Hertfordshire | HP2 4UL | bam.***** | 1874 | $1,170,957,863 | 1,800 | N/A | N/A | N/A |
| 55 | Vivo Defence Services LIMITED | Unitedkingdom | North Brunton | First Floor | Newcastle Upon Tyne, Tyne and Wear | NE12 8BU | N/A | 2019 | $1,161,746,886 | 1,560 | N/A | N/A | N/A |
| 56 | Mclaughlin & Harvey Holdings LIMITED | Unitedkingdom | Newtownabbey | 15 Trench Road | Antrim and Newtownabbey | BT36 4TY | mclh.***** | 2015 | $1,106,937,005 | 872 | N/A | N/A | N/A |
| 57 | Lovell Partnerships LIMITED | Unitedkingdom | Bolehall | Marston Park | Staffordshire | B78 3HN | lovell.***** | 1971 | $1,099,985,419 | 1,192 | N/A | N/A | N/A |
| 58 | Tclarke Contracting LIMITED | Unitedkingdom | Moorgate | 30 St. Mary Axe | London | EC3A 8BF | tclarke.***** | 1923 | $1,071,032,594 | 760 | N/A | N/A | N/A |
| 59 | Kier Infrastructure And Overseas LIMITED | Unitedkingdom | Cadishead | 2nd Floor Optimum House | Manchester, Greater Manchester | M50 3XP | kier.***** | 1860 | $1,017,619,998 | 1,150 | N/A | N/A | N/A |
| 60 | Equans Regeneration LIMITED | Unitedkingdom | North Brunton | First Floor, Neon,q10 | Newcastle Upon Tyne, Tyne and Wear | NE12 8BU | engie.***** | 1983 | $992,669,799 | 2,546 | N/A | N/A | N/A |
| 61 | Multiplex Construction Europe LIMITED | Unitedkingdom | Moorgate | 2nd Floor | London | EC2M 3XD | N/A | 1965 | $988,835,061 | 644 | N/A | N/A | N/A |
| 62 | Bam Construction LIMITED | Unitedkingdom | Potten End | Breakspear Park | Hertfordshire | HP2 4FL | bam.***** | 1998 | $987,397,510 | 442 | N/A | N/A | N/A |
| 63 | Keepmoat Homes LIMITED | Unitedkingdom | Hyde Park | Keepmoat | Doncaster, South Yorkshire | DN4 5PL | keepmoat.***** | 1987 | $971,719,793 | 1,041 | N/A | N/A | N/A |
| 64 | Arris Global LTD. | Unitedkingdom | Saint Giles | 16 Great Queen Street | London | WC2B 5AH | commscope.***** | 1982 | $947,958,000 | 296 | N/A | N/A | N/A |
| 65 | Volkerfitzpatrick LIMITED | Unitedkingdom | Hoddesdon | Hertford Road | Hertfordshire | EN11 9BX | volkerfitzpatrick.***** | 1989 | $924,809,514 | 1,020 | N/A | N/A | N/A |
| 66 | Build King Construction LIMITED | Unitedkingdom | Stepney | 1 Blossom Yard | London | E1 6RS | N/A | 1978 | $921,501,909 | 1,441 | N/A | N/A | N/A |
| 67 | Buckingham Group Contracting LIMITED | Unitedkingdom | Manchester | Grant Thornton UK | Manchester, Greater Manchester | M1 4PB | buckinghamgroup.***** | 1955 | $887,566,751 | 658 | N/A | N/A | N/A |
| 68 | Eurovia UK LIMITED | Unitedkingdom | Horsham | Albion House | West Sussex | RH12 2RW | ringway.***** | 1976 | $879,055,068 | 31 | N/A | N/A | N/A |
| 69 | St William Homes Llp | Unitedkingdom | Herne Hill | 15b St. George Wharf | London | SW8 2LE | berkeleygroup.***** | 2014 | $848,490,332 | 236 | N/A | N/A | N/A |
| 70 | Mclaughlin & Harvey LIMITED | Unitedkingdom | Newtownabbey | 15 Trench Road | Antrim and Newtownabbey | BT36 4TY | mclh.***** | 1993 | $844,727,656 | 582 | N/A | N/A | N/A |
| 71 | Ng Bailey Group LIMITED | Unitedkingdom | Leeds | Ground Floor (suite T), Arlington Business Centre Building | Leeds, West Yorkshire | LS11 0DL | ngbailey.***** | 1921 | $822,382,596 | 3,468 | N/A | N/A | N/A |
| 72 | Robertson Construction Group LIMITED | Unitedkingdom | Stirling | Robertson House | Stirling | FK9 4TZ | robertsonhomes.***** | 1966 | $797,750,229 | 268 | N/A | N/A | N/A |
| 73 | Altrad Employment Services LIMITED | Unitedkingdom | Stretton | 6-7 Lyncastle Way Barleycastle Lane | Warrington | WA4 4ST | capeplc.***** | 2018 | $778,140,533 | 8,662 | N/A | N/A | N/A |
| 74 | Dalkia Group LIMITED | Unitedkingdom | Staines-upon-thames | Twenty, Kingston Road | Surrey | TW18 4LG | N/A | 2015 | $772,009,464 | 4,064 | N/A | N/A | N/A |
| 75 | F M Conway LIMITED | Unitedkingdom | Otford | Conway House | Kent | TN14 5EL | fmconway.***** | 1958 | $769,540,975 | 2,332 | N/A | N/A | N/A |
| 76 | Midgard LTD | Unitedkingdom | Borehamwood | 4 Elstree Way | Hertfordshire | WD6 1RN | jrlgroup.***** | 2006 | $763,340,476 | 229 | N/A | N/A | N/A |
| 77 | Brickability Group PLC | Unitedkingdom | Bracknell | Queensgate House | Bracknell Forest | RG12 1RB | brickabilitygroupplc.***** | 2017 | $753,948,386 | 813 | N/A | N/A | N/A |
| 78 | Network Plus Services LTD | Unitedkingdom | Boothstown | Chaddock Lane | Manchester, Greater Manchester | M28 1XW | networkplus.***** | 1993 | $739,742,988 | 2,423 | N/A | N/A | N/A |
| 79 | Kier Transportation LIMITED | Unitedkingdom | Cadishead | 2nd Floor Optimum House | Manchester, Greater Manchester | M50 3XP | N/A | 2005 | $727,564,497 | 2,511 | N/A | N/A | N/A |
| 80 | Hill Partnerships LIMITED | Unitedkingdom | Waltham Abbey | Gunpowder Mill | Essex | EN9 1BN | hill.***** | 1999 | $724,272,222 | 629 | N/A | N/A | N/A |
| 81 | Laing O'rourke Services LIMITED | Unitedkingdom | Longfield | Bridge Place | Kent | DA2 6SN | laingorourke.***** | 2001 | $710,551,136 | 6,917 | N/A | N/A | N/A |
| 82 | Amey Lafarge Joint Venture | Unitedkingdom | Anthill Common | Forum 1 | Hampshire | PO15 7PA | N/A | 2002 | $710,413,851 | 11,000 | N/A | N/A | N/A |
| 83 | Bylor Services LIMITED | Unitedkingdom | Longfield | Bridge Place, Anchor Boulevard | Kent | DA2 6SN | N/A | 2016 | $688,631,655 | 5,600 | N/A | N/A | N/A |
| 84 | Isg Fit Out LIMITED | Unitedkingdom | Rotherhithe | 1 More London Place | London | SE1 2AF | imxsoftware.***** | 2009 | $683,660,621 | 500 | N/A | N/A | N/A |
| 85 | M Group Highways LIMITED | Unitedkingdom | Stevenage | Abel Smith House | Hertfordshire | SG1 2ST | morrisonrecruit.***** | 1973 | $676,928,893 | 1,839 | N/A | N/A | N/A |
| 86 | Ferrovial Construction (UK) LIMITED | Unitedkingdom | London | 3rd Floor Building 5 | London | W4 5YF | ferrovial.***** | 2002 | $673,813,549 | 563 | N/A | N/A | N/A |
| 87 | Tsl LIMITED | Unitedkingdom | Gerrards Cross | Chalfont Park House | Buckinghamshire | SL9 0DZ | tslprojects.***** | 2002 | $667,558,806 | 252 | N/A | N/A | N/A |
| 88 | Isg Retail LIMITED | Unitedkingdom | Rotherhithe | 1 More London Place | London | SE1 2AF | N/A | 1992 | $663,063,154 | 515 | N/A | N/A | N/A |
| 89 | Balfour Beatty Utility Solutions LIMITED | Unitedkingdom | Canary Wharf | 5 Churchill Place | London | E14 5HU | balfourbeatty.***** | 1972 | $663,032,748 | 6,500 | N/A | N/A | N/A |
| 90 | Northern Gas Networks LIMITED | Unitedkingdom | Pendas Fields | 1100 Century Way | Leeds, West Yorkshire | LS15 8TU | northerngasnetworks.***** | 2004 | $662,358,796 | 1,589 | N/A | N/A | N/A |
| 91 | Tilbury Douglas Construction LIMITED | Unitedkingdom | Whipton | Oberon Road | Devon | EX1 3QD | interserve.***** | 1935 | $657,409,744 | 1,035 | N/A | N/A | N/A |
| 92 | Isg Construction LIMITED | Unitedkingdom | Rotherhithe | Ernst & Young Llp | London | SE1 2AF | N/A | 1948 | $655,788,785 | 890 | N/A | N/A | N/A |
| 93 | Vistry Partnerships LIMITED | Unitedkingdom | West Malling | 11 Tower View | Kent | ME19 4UY | N/A | 1964 | $654,129,088 | 1,223 | N/A | N/A | N/A |
| 94 | J.N. Bentley LIMITED | Unitedkingdom | Skipton | Snaygill Industrial Estate | North Yorkshire | BD23 2QR | jnbentley.***** | 1972 | $646,814,458 | 2,035 | N/A | N/A | N/A |
| 95 | Northstone (ni) LIMITED | Unitedkingdom | Old Forge | 99 Kingsway | Belfast | BT17 9NU | farrans.***** | 1941 | $638,762,872 | 1,049 | N/A | N/A | N/A |
| 96 | Mott Macdonald Bentley LTD | Unitedkingdom | Skipton | Snaygill Indstl Estate | North Yorkshire | BD23 2QR | jnbentley.***** | 1999 | $638,223,377 | 200 | N/A | N/A | N/A |
| 97 | Ringway Infrastructure Services LIMITED | Unitedkingdom | Horsham | Albion House | West Sussex | RH12 2RW | ringway.***** | 1992 | $637,675,250 | 1,521 | N/A | N/A | N/A |
| 98 | Altrad Services LIMITED | Unitedkingdom | Warrington | 7 Asher Court | Warrington | WA4 4ST | capeplc.***** | 1997 | $626,799,350 | 2,309 | N/A | N/A | N/A |
| 99 | John Paul Construction LIMITED | Unitedkingdom | Ealing | 58 Uxbridge Road, Ealing | London | W5 2ST | johnpaulconstruction.***** | 2010 | $617,562,574 | 484 | N/A | N/A | N/A |
| 100 | Ovo (s) Gas LIMITED | Unitedkingdom | Bristol | Temple Quay | City of Bristol | BS1 6DG | N/A | 1992 | $615,240,316 | 353 | N/A | N/A | N/A |