| WORD | NAME | DESCRIPTION | |
| MACHINE | Industrials | 401020 - Machinery Manufacturing | Full Description |
| MACHINEOTHER | Industrials | 40102030 - Other Machinery Manufacturing | Full Description |
| MACHINEPARTS | Industrials | 40102020 - Industrial Machine Parts and Support Equipment | Full Description |
| MAR | Country IDs | Morocco | |
| MasterLP | Universe IDs - Other USA | Master Limited Partnerships | |
| MATCONSTR | Non-Energy Materials | 451535 - Construction Materials | Full Description |
| MATCONSTRGEN | Non-Energy Materials | 45153515 - General Construction Materials Manufacturing | Full Description |
| MATCONSTRHEAVY | Non-Energy Materials | 45153520 - Heavy Building Material and Aggregate Products | Full Description |
| MATDISTRIB | Industrials | 40152015 - Materials Distributors | Full Description |
| MATDIV | Non-Energy Materials | 45202015 - Diversified Materials | Full Description |
| MATERIALS | Non-Energy Materials | 45 - Non-Energy Materials | Full Description |
| MATOTHER | Non-Energy Materials | 452020 - Other Materials | Full Description |
| MCO | Country IDs | Monaco | |
| MDA | Country IDs | Moldova | |
| MEASURE | Technology | 55151045 - Test and Measurement Equipment | Full Description |
| MEDDEVICESDIV | Healthcare | 35201515 - Diversified Medical Devices and Instruments | Full Description |
| MEDDEVICESGEN | Healthcare | 352015 - General Medical Devices | Full Description |
| MEDDEVICESOTHER | Healthcare | 352020 - Other Medical Devices | Full Description |
| MEDDEVICESSPECIAL | Healthcare | 35202015 - Specialized Medical Devices | Full Description |
| MEDIAELECTRONICS | Technology | 55151025 - Media Industry Electronics Manufacturing | Full Description |
| MEDIAPUB | Consumer Services | 151510 - Media and Publishing Services | Full Description |
| MEDIAPUBSS | Consumer Services | 1515 - Media and Publishing Services | Full Description |
| MEDSUPPLIES | Healthcare | 35202010 - Medical Supplies | Full Description |
| MERCHRETAIL | Consumer Non-Cyclicals | 50101520 - General Merchandise Retailers | Full Description |
| METAL | Non-Energy Materials | 451510 - Metal Products | Full Description |
| METALOTHER | Non-Energy Materials | 45151015 - Other Metal Product Manufacturing | Full Description |
| METALPARTS | Non-Energy Materials | 45151010 - Metal Parts and Component Manufacturing | Full Description |
| METALPRIMARY | Non-Energy Materials | 45151020 - Primary Metals Products | Full Description |
| MEX | Country IDs | Mexico | |
| MFRBUILDING | Consumer Cyclicals | 20152020 - Manufactured Building Makers Since 2020-07-19, previously MFRBUILDING.XX1 | Full Description |
| MFRBUILDING.XX1 | Finance | 30251015 - Manufactured Building Makers Discontinued 2020-07-19, replaced by MFRBUILDING | Full Description |
| MFRPROD | Non-Energy Materials | 4520 - Manufactured Products | Full Description |
| MicroCap | Universe IDs - Other USA | MicroCap | |
| MidCap | Universe IDs - Other USA | Mid Cap | |
| MIDSTREAMENERGY | Energy | 251515 - Midstream Energy | Full Description |
| MINERAL | Non-Energy Materials | 451515 - Minerals | Full Description |
| MINING | Non-Energy Materials | 4515 - Mining and Mineral Products | Full Description |
| MININGOTHER | Non-Energy Materials | 451530 - Other Mining | Full Description |
| MININGSTREAMING | Non-Energy Materials | 45153020 - Streaming and Royalties | Full Description |
| MIXMETALMINERAL | Non-Energy Materials | 451520 - Mixed Metal and Mineral Products | Full Description |
| MKD | Country IDs | Macedonia | |
| MKTINGPRINTING | Business Services | 101010 - Marketing and Printing Services | Full Description |
| MLT | Country IDs | Malta | |
| MNE | Country IDs | Montenegro | |
| MNG | Country IDs | Mongolia | |
| MSR | Country IDs | Montserrat | |
| MULTIDELIVCARE | Healthcare | 35151525 - Multi-Delivery-Type Patient Care | Full Description |
| MUS | Country IDs | Mauritius | |
| MUSCULOSKELETAL | Healthcare | 35102040 - Musculoskeletal System Biopharmaceuticals | Full Description |
| MWI | Country IDs | Malawi | |
| MYS | Country IDs | Malaysia | |
| MYT | Country IDs | Mayotte |