| Isb AS | Construction | 2021 |
| Isoenergi AS | Construction | 2008 |
| Isoenergi Invest AS | Real estate | 2016 |
| Jiks Eiendom AS | Real estate | 2003 |
| JKB AS | Professional & scientific | 2017 |
| Johansen Kran Og Transport AS | Transport & logistics | 2020 |
| John Hæhre AS | Construction | 2016 |
| Johnson Metall AB | Wholesale & retail | 2016 |
| Johnson Metall AS | Wholesale & retail | 1998 |
| Juelsen Holding AS | | 2023 |
| K R Anlegg AS | Construction | 2013 |
| Ka-Pre Eiendom AS | Real estate | 2005 |
| Ka-Pre Holding AS | Wholesale & retail | 2022 |
| Ka-Pre Norge AS | Wholesale & retail | 2001 |
| Kaboom Invest AS | | 2021 |
| Kaggefossveien Eiendom AS | Real estate | 2021 |
| Kampestad Tomter AS | Real estate | 2026 |
| Kampestad Utvikling AS | Real estate | 2025 |
| Katfoss Industripark AS | Real estate | 2026 |
| Kattehotellet AS | Other services | 2024 |
| Kbraathen AS | Construction | 2022 |
| KDB Holding AS | Real estate | 2020 |
| KDS Eiendom AS | Real estate | 2019 |
| Kerim Frisøren AS | Other services | 2015 |
| Khn-Holding AS | Real estate | 2020 |
| Kilden Kiropraktikk AS | Health & social care | 2021 |
| Kjell Finsrud AS | Construction | 2011 |
| Kjell Ivar Bråten Holding AS | Financial services | 2018 |
| KKJ Invest AS | Hospitality | 2011 |
| Kleiv Invest AS | Real estate | 2005 |
| KLF Invest. AS | | 2023 |
| KLH AS | | 2012 |
| Kloppa Holding AS | Hospitality | 2024 |
| Kløver Ess AS | | 2016 |
| Knarten AS | Real estate | 2012 |
| Knarten Holding AS | Construction | 2007 |
| Knarten Holding II AS | Construction | 2023 |
| Knive AS | Transport & logistics | 1985 |
| Kopland Eiendom AS | Real estate | 2006 |
| Kopland Holding AS | Arts & recreation | 2005 |
| Kovert AS | Information & communication | 2020 |
| Kraftia Energi AS | Energy | 1998 |
| Kraftia Tjenester AS | Energy | 1998 |
| Krokåsen Holding AS | | 2021 |
| Krona Kafé Og Catering AS | Hospitality | 2014 |
| Kronen Bygg AS | Construction | 2017 |
| Krsand AS | | 2019 |
| Ks-Prosjekt AS | Professional & scientific | 2005 |
| Kvaase Holding AS | | 2023 |
| KVF Holding AS | Construction | 2011 |
| Laborem Invest AS | Wholesale & retail | 2015 |
| Lagerbygg Vikersund AS | Administrative & support | 2025 |
| Langelars Holding AS | Wholesale & retail | 2010 |
| Langerud Holding AS | Financial services | 2012 |
| Larsa Invest AS | Financial services | 2017 |
| Lassen Invest AS | | 2025 |
| Lastebilsenteret Modum AS | Real estate | 2007 |
| Lennsmannsgården AS | Real estate | 2000 |
| Lib AS | | 2015 |
| Lien Transport Og Veiservice AS | Transport & logistics | 2013 |
| Linda Røed AS | Wholesale & retail | 2017 |
| Lindetun Holding AS | Real estate | 2017 |
| Lindetun Invest AS | Real estate | 2015 |
| LK Utleie AS | Administrative & support | 1988 |
| Logable AS | Information & communication | 2026 |
| Logos Eiendom AS | Professional & scientific | 2014 |
| Lord & Lady Ans | Other services | 1995 |
| Luga Eiendom AS | Real estate | 1998 |
| Løiten Holding AS | Real estate | 2022 |
| Lønneberget BHG AS | Education | 2015 |
| M.P Renna AS | Wholesale & retail | 2023 |
| Ma - So AS | Wholesale & retail | 2015 |
| Ma Media AS | Professional & scientific | 2022 |
| Magna Musica AS | Arts & recreation | 2022 |
| Magne Hæhre AS | Financial services | 2014 |
| Magnussen Engineering AS | Real estate | 2014 |
| Mahi Maskin AS | Construction | 2023 |
| Marta Manani Albornoz AS | Wholesale & retail | 2017 |
| Martinius AS | Real estate | 2005 |
| Martins Maskinservice AS | Manufacturing | 2012 |
| Matnyttig AS | Hospitality | 1998 |
| Mats Alexander Invest AS | Professional & scientific | 2021 |
| Melåveien SA | Real estate | 1972 |
| Menoma AS | Wholesale & retail | 2022 |
| Menoma Eiendom AS | Real estate | 2024 |
| Ment AS | Construction | 2024 |
| MFH Invest AS | | 2026 |
| Midtnett AS | Energy | 2016 |
| Mini Wigdal AS | Administrative & support | 2020 |
| Mivax Anlegg AS | Construction | 2025 |
| MM Berlin AS | Real estate | 2025 |
| MMH AS | Construction | 2013 |
| Mobra AS | Wholesale & retail | 2004 |
| Modum Bad Gårdsdrift AS | Real estate | 2022 |
| Modum Begravelsbyrå Sognelien M Ef | Other services | 1986 |
| Modum Billakksenter AS | Other services | 2012 |
| Modum Bygg AS | Wholesale & retail | 1990 |
| Modum Dyreklinikk AS | Professional & scientific | 2004 |
| Modum Eiendomsutvikling AS | Real estate | 2008 |
| Modum Kommunes Skoger | Agriculture & fishing | 1995 |