| Client name | City | Country |
|---|---|---|
| Mechanica C.V. Delft | Delft | Netherlands |
| Merck KGaA | Darmstadt | Germany |
| MERCON Sp. z o.o. | Wloclawek | Poland |
| MESSER LLC | Houston | United States |
| Messer SE & Co. KGaA | Bad Soden | Germany |
| Methanex | Houston | United States |
| Methanex Corporation | Medicine Hat | Canada |
| Methanex Corporation Ltd. | Medicine Hat | Canada |
| Methanex New Zealand Limited | New Plymouth | New Zealand |
| Methanex Trinidad (Titan) Unlimited | Point Lisas | Trinidad and Tobago |
| Methanex USA, LLC | Geismar | United States |
| Metior Industrieanl. Planungs- & Beratungs- GmbH | Graz | Austria |
| Metra Energie Messtechnik GmbH | Speyer | Germany |
| Metso Automation GmbH | Leverkusen | Germany |
| Microfinish Valves Pvt. Ltd. | Dharwad | India |
| Microflex Services GmbH | Hamburg | Germany |
| Middle East Oilfield Services L.L.C. | Ruwi, Muscat | Oman |
| MIL Controls Limited | Aluva | India |
| Minco (India) Flow Elements Pvt. Ltd. | Mapusa | India |
| Minco India Pvt. Ltd. | MAPUSA | India |
| MiRO Mineraloelraffinerie Oberrhein GmbH & Co. KG | Karlsruhe | Germany |
| MiRO Mineralölraffinerie Oberrhein GmbH & Co. KG | Karlsruhe | Germany |
| Mitsubishi Hitachi Power Systems India Pvt. Ltd. | Bangalore | India |
| Mitsubishi Power Europe GmbH | Duisburg | Germany |
| MMEC Mannesmann GmbH | Düsseldorf | Germany |