| 7499 | Managers, artists | |
| 7499 | Managers, entertainers | |
| 7499 | Managers, sports figures | |
| 6712 | Managing investment funds, closed-end | |
| 6712 | Managing investment funds, open-end | |
| 6712 | Managing mutual funds, on contract | |
| 7414 | Managing office of dentist, general | |
| 7414 | Managing office of dentist, specialist | |
| 7414 | Managing office of doctors | |
| 7414 | Managing office of lawyers | |
| 7414 | Managing office of physicians and surgeons | |
| 7020 | Managing sr citizens self contained apartment | |
| 3692 | Mandolins and parts, manufacturing | |
| 2922 | Mandrels (i.e., machine tool accessory), manufacturing | |
| 2411 | Manganese dioxide, manufacturing | |
| 2710 | Manganese metal ferro-alloys, manufacturing | |
| 1320 | Manganese ore dressing and beneficiating | |
| 1320 | Manganese ore mining | |
| 1310 | Manganiferous iron ore mining | |
| 1310 | Manganiferous ore valued for iron content, mining | |
| 1320 | Manganite mining | |
| 0111 | Mangel growing | |
| 2930 | Mangles and ironers, domestic, manufacturing | |
| 2411 | Mangrove extract, manufacturing | |
| 4520 | Manhole construction, contractors | |
| 2695 | Manhole covers and frames, concrete, manufacturing | |
| 2731 | Manhole covers, cast iron, manufacturing | |
| 9302 | Manicure and pedicure salons | |
| 2424 | Manicure preparations, manufacturing | |
| 5139 | Manicure preparations, wholesale | |
| 9302 | Manicurist | |
| 2221 | Manifold business forms, printing | |
| 5139 | Manifold business forms, wholesale | |
| 3430 | Manifolds (i.e., intake and exhaust), automotive and truck gasoline engine, manufacturing | |
| 2109 | Manila folders, die-cut, made from purchased paper or paperboard | |
| 2430 | Man-made cellulosic fibres, manufacturing | |
| 5131 | Man-made fabric, piece goods, wholesale | |
| 1711 | Man-made fabrics, broad-woven, weaving | |
| 1729 | Man-made fibre fabric, narrow woven (i.e., 30 cm/12 in. or less in width), weaving | |
| 1711 | Man-made fibre thread, manufacturing | |