| M.J. Eriksson A/S | 2635 | Ishøj |
| Madera aps | 7361 | Ejstrupholm |
| Mariendal | 9000 | Aalborg |
| Marlon Tørmørtel A/S | 8740 | Brædstrup |
| Marmorline & Co. A/S | 7200 | Grindsted |
| Maskiner A/S | 8700 | Horsens |
| Master Builders Solutions Denmark A/S | 6230 | Rødekro |
| Masytec A/S | 2605 | Brøndby |
| Max Weishaupt A/S | 2600 | Glostrup |
| Maycon A/S | 4700 | Næstved |
| Mega Overflade-Teknik A/S | 7280 | Sdr. Felding |
| Menard GmbH | 21220 | Seevetal |
| MENY Kaffe | 9400 | Nørresundby |
| Merton A/S | 8600 | Silkeborg |
| Microsolutions A/S | 8700 | Horsens |
| Midtjydsk Beton-vare og Elementfabrik A/S | 7400 | Herning |
| Midtjydsk Kran & Elektro a/s | 7400 | Herning |
| Midtjysk Albyg A/S | 7490 | Aulum |
| Mila Beslag A/S | 3000 | Helsingør |
| Mirit Glas A/S | 2730 | Herlev |
| MLI Murerentreprise A/S | 8800 | Viborg |
| Mobilhouse A/S | 7000 | Fredericia |
| Modul-System HH A/S | 2605 | Brøndby |
| Mogens Rasmussen, Middelfart A/S | 5500 | Middelfart |
| Mogens V. Zeltner A/S | 3520 | Farum |
| Moland A/S | 7800 | Skive |
| Molio | 2730 | Herlev |
| Molt Wengel Advokatpartnerselskab | 2100 | København Ø |
| MRMOTECH ApS | 8300 | Odder |
| MTDK A/S - AMT Trailer | 8940 | Randers SV |
| MTO electric a/s | 7100 | Vejle |
| Mul10 Metal A/S | 7130 | Juelsminde |
| Mul10 Prosafe A/S | 7130 | Juelsminde |
| Multi Køl & Energi A/S | 8220 | Brabrand |
| Multi Montage Stoholm A/S | 7850 | Stoholm J |
| Multi-Services ApS | 7000 | Fredericia |
| MX Door ApS | 9600 | Aars |
| MYHLENBERG BYG A/S | 9510 | Arden |
| Meinertz A/S | 8700 | Horsens |