| # | Company name | Role | # of projects |
|---|---|---|---|
| 41 | MKK Consulting Engineers, Inc. | MEP engineering | 6 |
| 42 | MN Ingenieure GmbH | MEP engineering | 3 |
| 43 | Mn-Manuel Nebot Ingeniería, S.L. | MEP engineering | 1 |
| 44 | Modus Engineering | MEP engineering | 2 |
| 45 | Moore Engineers PC | MEP engineering | 4 |
| 46 | Mott MacDonald | MEP engineering | 2 |
| 47 | Mottola Rini Engineers, P.C. | MEP engineering | 10 |
| 48 | MTL Associates | MEP engineering | 1 |
| 49 | mTT Consultants | MEP engineering | 7 |
| 50 | Müller & Bleher Filderstadt GmbH & Co. KG | MEP engineering | 1 |