| Siv Ing Bjørn Gulbrandsen AS | Heggedal | 2025 |
| Siv Ing Braathen-Sømme AS | Drammen | 2014 |
| Siv Ing CK AS | Sofiemyr | 2013 |
| Siv Ing Eldrup AS | Stathelle | 2002 |
| Siv Ing Erling F Johnsen AS | Oslo | 1988 |
| Siv Ing Helge Andreassen AS | Mysen | 2000 |
| Siv Ing Ingar Brauti AS | Asker | 1994 |
| Siv Ing Inge Johansen AS | Nærsnes | 1993 |
| Siv Ing J. Berger AS | Nærsnes | 2014 |
| Siv Ing JP Dybdahl AS | Jar | 1993 |
| Siv Ing JT Indrebø Engineering AS | Ås | 2016 |
| Siv Ing Kurt Rønning AS | Melbu | 1998 |
| Siv Ing Myklebust AS | Skodje | 2024 |
| Siv Ing Nils Hjorthol AS | Billingstad | 1994 |
| Siv Ing Per Olav Haughom AS | Tonstad | 1998 |
| Siv Ing Per Tefre AS | Oslo | 1989 |
| Siv Ing Pål Pettersen Nuf | Rotsund | 2008 |
| Siv Ing Tor Loftesnes AS | Sogndal | 1997 |
| Siv Ing Yngve Fredriksen AS | Svolvær | 1990 |
| Siv Ing Øivind B Berntsen AS | Arendal | 1990 |
| Siv Ing Øyvind Stokke AS | Tønsberg | 2010 |
| Siv Ing. a. Kvingedal AS | Hamarvik | 2016 |
| Siv Jensen AS | Oslo | 2023 |
| Siv Jensen Holding AS | Oslo | 2022 |
| Siv Støldal AS | Bjørøyhamn | 2012 |
| Siv Sunde Consulting AS | Stavanger | 2024 |
| Siv. Ing H Storli AS | Røros | 2005 |
| Siv. Ing Sverre Melby AS | Sande I Vestfold | 2012 |
| Siv. Ing Sverre Stålem AS | Hemnesberget | 1996 |
| Siv. Ing. a. Godal AS | Fana | 2025 |
| Siv. Ing. Dordi Skjevling AS | Hønefoss | 2024 |
| Siv. Ing. Einar Piene AS | Oslo | 2014 |
| Siv. Ing. Engeset AS | Røyken | 2024 |
| Siv. Ing. Espen Strand AS | Bærums Verk | 2012 |
| Siv. Ing. Fredrik Normann AS | Oslo | 2006 |
| Siv. Ing. H. Kjelstad AS | Sande I Sunnfjord | 2014 |
| Siv. Ing. Hans Narvestad AS | Porsgrunn | 2024 |
| Siv. Ing. Harald Moe & Co AS | Eiksmarka | 2014 |
| Siv. Ing. Jan Krogstad AS | Oslo | 2011 |
| Siv. Ing. Jan Lian AS | Overhalla | 2012 |
| Siv. Ing. Joachim Holm AS | Drøbak | 2014 |
| Siv. Ing. Knut P Taranger AS | Nesøya | 2000 |
| Siv. Ing. Oddgeir Odlo AS | Ringebu | 2022 |
| Siv. Ing. Stener Sørensen AS | Drammen | 2014 |
| Siv. Ing. Tobias Dahle AS | Leikanger | 2016 |
| Siv.Ark Einar Myraker Mnal Npa AS | Arendal | 2018 |
| Siv.Ing Arne Hauge AS | Oslo | 2019 |
| Siv.Ing Eivind Pettersen AS | Hønefoss | 2020 |
| Siv.Ing Hjortaas AS | Fredrikstad | 2021 |
| Siv.Ing Kjell Gurigard AS | Lillehammer | 2005 |
| Siv.Ing Morten Kjelsaas AS | Oslo | 2021 |
| Siv.Ing Nina Rongved AS | Hønefoss | 2009 |
| Siv.Ing Per Ø Hansen AS | Brumunddal | 2002 |
| Siv.Ing. A.Nygård AS | Fauske | 1995 |
| Siv.Ing. Arnbjørn Kulbrandstad AS | Sellebakk | 2018 |
| Siv.Ing. Danielsen AS | Tiller | 2000 |
| Siv.Ing. F.M. Haaland AS | Kråkerøy | 2019 |
| Siv.Ing. Finn-Erik Nilsen AS | Oslo | 2009 |
| Siv.Ing. Ketil Pettersen AS | Bodø | 2019 |
| Siv.Ing. Leivestad AS | Oslo | 2019 |
| Siv.Ing. Pål Holst AS | Ulset | 2025 |
| Siv.Ing. Sæther AS | Buvika | 2012 |
| Siv.Ing. Terje Eknes AS | Ås | 2012 |
| Siv.Ing. Torgeir Viddal AS | Sandnes | 2016 |
| Siv.Øk Thore Arne Olsen AS | Larvik | 2020 |
| Sivas AS | Mandal | 1992 |
| Sivcom AS | Asker | 2019 |
| Sivcon AS | Kristiansand S | 2006 |
| Siver AS | Fornebu | 2020 |
| SIVER1 AS | Fornebu | 2022 |
| SIVER2 AS | Fornebu | 2022 |
| Sivertsen - Skogum Consult Ans | Skjåk | 1990 |
| Sivertsen Energy AS | Randaberg | 2016 |
| Sivertsen Reklame & Design AS | Mosby | 2017 |
| Sivico AS | Hjellestad | 2026 |
| Sivil Ingeniør Marius Bakken AS | Hamar | 2022 |
| Sivilarkitekt Berge AS | Kleppe | 2011 |
| Sivilarkitekt Erik Asbjørnsen AS | Kristiansand S | 2012 |
| Sivilarkitekt Espen Surnevik AS | Oslo | 2012 |
| Sivilarkitekt Gunnar Knutsen AS | Lillesand | 1997 |
| Sivilarkitekt Henry Benson AS | Mjølkeråen | 1998 |
| Sivilarkitekt Knut Haarklau AS | Lillesand | 2021 |
| Sivilarkitekt Kristian Asdal AS | Arendal | 2017 |
| Sivilarkitekt Kristin Gustavsen AS | Hundvåg | 2015 |
| Sivilarkitekt Leif Larsen Holding AS | Sandnes | 2005 |
| Sivilarkitekt Løvdahl AS | Lillesand | 1996 |
| Sivilarkitekt Mnal Einar Martin Lundstad AS | Hønefoss | 2018 |
| Sivilarkitekt Mnal Jonny Johansen AS | Stavanger | 2007 |
| Sivilarkitekt Mnal Leif Larsen AS | Sandnes | 1998 |
| Sivilarkitekt Mnal Peder Blindheim AS | Drammen | 2006 |
| Sivilarkitekt Nils-Jacob Lugg AS | Tønsberg | 1998 |
| Sivilarkitekt Odd Håkon Byberg AS | Trondheim | 2008 |
| Sivilarkitekt Per Joar Østhus AS | Oslo | 2017 |
| Sivilarkitekt Rolf Skjelstad AS | Stavanger | 2014 |
| Sivilarkitekt S. Bothner Og Planhuset AS | Kragerø | 2020 |
| Sivilarkitekt Silje Søntvedt AS | Skien | 2022 |
| Sivilarkitekt Tom - Rich. Kristiansen AS | Engelsviken | 2013 |
| Sivilarkitekt Tor Helge Valen AS | Hjellestad | 2009 |
| Sivilarkitekt Tordis Hoem AS | Oslo | 1996 |
| Sivilarkitektene Hoem AS | Stavanger | 1998 |