| Speed Potion AS | Information & communication | 2016 |
| Spermvital AS | Professional & scientific | 2008 |
| Spermvital Invest AS | Agriculture & fishing | 2011 |
| Spillorama Hamar AS | Arts & recreation | 2010 |
| SPM Sport AS | Wholesale & retail | 2026 |
| Sponsorselskapet Først Til Mølla AS | Professional & scientific | 1999 |
| Sportadventure AS | Wholesale & retail | 2015 |
| Sportstech AS | Information & communication | 2026 |
| Sportsvenue AS | Information & communication | 2026 |
| Sprett Fysioterapi AS | Health & social care | 2025 |
| Srl-Holding AS | Real estate | 2017 |
| Sru Invest AS | Professional & scientific | 2005 |
| SS Automation AS | Construction | 2026 |
| SS Industry AS | Professional & scientific | 2017 |
| Sseiendom AS | Professional & scientific | 2018 |
| Ssholding AS | Professional & scientific | 2022 |
| ST. Olavsgate Invest AS | Real estate | 2017 |
| Stadion 16.32.6 AS | Wholesale & retail | 2005 |
| Stadion Reiseeffekter AS | Wholesale & retail | 2013 |
| Stadion Tannklinikk AS | Health & social care | 2023 |
| Stafsberg Holding AS | | 2021 |
| Stafsberg Invest AS | | 2026 |
| Stafsbergsenteret AS | Real estate | 2021 |
| Stafsbergvegen 152 B AS | Real estate | 2021 |
| Stafsbergvegen 21 AS | Real estate | 2021 |
| Stafsbergvegen Utvikling AS | Construction | 2025 |
| Stallgården Hamar AS | Hospitality | 2022 |
| Stangebrua Auto Service AS | Other services | 2021 |
| Stangevegen 22 AS | Real estate | 2023 |
| Stasjonsdrift Holding AS | Real estate | 2007 |
| Staslin Kjøtt AS | Manufacturing | 2019 |
| Stat Stick Games AS | Information & communication | 2026 |
| Steffen Dyre Hansen Holding AS | Financial services | 2015 |
| Stein Utleie & Service AS | Administrative & support | 2005 |
| Steinkjer Fylkeshus AS | Real estate | 2021 |
| Stemmen Utbyggingsselskap AS | Real estate | 2021 |
| Stenberg Invest AS | Real estate | 2005 |
| Stenfjell AS | Financial services | 2005 |
| Stenrik Holding AS | Financial services | 2015 |
| Sterud Bolig AS | Real estate | 2020 |
| Stian Dyre Hansen Holding AS | Financial services | 2015 |
| Stian Hoelseth AS | Professional & scientific | 2016 |
| Stig På AS | Information & communication | 2012 |
| Stitsj AS | Education | 2020 |
| Stjernfors AS | | 2019 |
| Stoikos Konsulent AS | Professional & scientific | 2012 |
| Stokk Energi AS | Professional & scientific | 2020 |
| Stone Hut AS | Financial services | 2014 |
| Storengen Ba-Consult AS | Professional & scientific | 2021 |
| Storgata 28 Eiendom AS | | 2026 |
| Storgata 84 Ans | Real estate | 2005 |
| Storhamar Auto AS | Other services | 2022 |
| Storhamar Autosalg AS | Wholesale & retail | 2026 |
| Storhamar Bil AS | Wholesale & retail | 2020 |
| Storhamar Bilpleie Og Bilvask AS | Other services | 2020 |
| Storhamar Bilservice AS | Other services | 2025 |
| Storhamar Crossfit AS | Arts & recreation | 2023 |
| Storhamar Eiendom AS | Real estate | 2007 |
| Storhamar Hockey AS | Arts & recreation | 2025 |
| Storhamar Legesenter AS | Health & social care | 2022 |
| Storhamar Tak AS | Construction | 2016 |
| Storhamargata 44 AS | Real estate | 2010 |
| Storhamargata 51B AS | Real estate | 2022 |
| Storhamargata 53 AS | Real estate | 2010 |
| Storhamargata 61 AS | Real estate | 2025 |
| Storhamargt 12 AS | | 2005 |
| Storhamarsenteret AS | Real estate | 1999 |
| Storhove Innovasjonsbygg AS | Real estate | 2016 |
| Storkiosk NR 49 Torggt Ans | Wholesale & retail | 2000 |
| Stormyra Eiendom Holding AS | Real estate | 2019 |
| Stortorget Legesenter Da | Health & social care | 2012 |
| Stortorget Øre Nese Hals AS | Health & social care | 2021 |
| Storyphone AS | Information & communication | 2019 |
| Strandgata 21 & 23 Hamar AS | Real estate | 2025 |
| Strandgata 22 Hamar AS | Real estate | 2025 |
| Strandgata 33 AS | Real estate | 2005 |
| Strandgata 71 Holding AS | Real estate | 2024 |
| Strandgata 71 Næring AS | Real estate | 2024 |
| Strandgaten 55 Da | Real estate | 2007 |
| Strandsonen Utvikling AS | Real estate | 2007 |
| Strandveien 151 a - AS | Real estate | 2009 |
| Stratcon AS | Professional & scientific | 1996 |
| Stratea AS | Professional & scientific | 2020 |
| Strato Frukt Og Tobakk M Nybakken & Co Ans | Wholesale & retail | 1987 |
| Strupeveien AS | Real estate | 2016 |
| Strøm & Strøm Holding AS | | 2024 |
| Studenterhytta AS | Hospitality | 1998 |
| Studio Camay AS | Wholesale & retail | 2024 |
| Studio Føy AS | Professional & scientific | 2016 |
| Studionsw AS | Professional & scientific | 1987 |
| Stupetårnet Eiendomsutleie AS | Real estate | 2017 |
| Stupetårnet Sentrum AS | Real estate | 2020 |
| Stupetårnet Utvikling AS | Administrative & support | 2019 |
| Stål I System AS | Wholesale & retail | 2014 |
| Sulland Auto AS | Wholesale & retail | 2022 |
| Sulland Bil AS | Wholesale & retail | 2021 |
| Sulland Gruppen AS | Other services | 2010 |
| Sulland Hamar AS | Other services | 1989 |
| Sundet Holding AS | | 2019 |
| Sundstrøm Haugen Invest AS | | 2020 |