| machine shop | magnesium foundries | mail-order houses |
| malt beverages | management consulting services | manifold business forms |
| manufactured ice | manufacturers agents | manufacturers representatives |
| manufacturing industries | marble | marble products manufacturers |
| marble products natural | marina | marine cargo handling |
| marine contractors | marine designers | marine fats |
| marine insurance | marking devices | masonry contractors |
| massage school | mattress manufacturers | meat market |
| meat packing plants | meat products | meats |
| meat wholesale | mechanical pencils | medical clinic |
| medical dental assistant technician schools | medical equipment rental | medical instruments |
| medical laboratories | medical school | medical service plans |
| membership organizations | membership sports | men's clothing retail |
| men clothing | men coats | mens clothing stores |
| men suits | mental health clinics | merchandising machine operators |
| metal-household furniture | metal coating | metal cutting type |
| metal finishing | metal goods | metal goods manufacturers |
| metal polishing | metal service centers | metals service offices |
| metal stamping | mexican restaurant | middle school |
| millwork | millwork contractors | millwork manufacturers |
| mineral conservation | minerals manufacturers | mini bike dealers |
| mini bikes | mining machinery | miscellaneous accessory stores |
| miscellaneous apparel stores | miscellaneous business credit institutions | miscellaneous commercial sectors |
| miscellaneous fabricated wire products | miscellaneous food stores | miscellaneous general merchandise stores |
| miscellaneous homefurnishings | miscellaneous nonmetallic minerals | miscellaneous personal service |
| miscellaneous publishing | miscellaneous retail stores | misses' dresses |
| misses' outerwear | mobile home community | mobile home dealers |
| mobile home parks | mobile homes | molder |
| monetary policy | monorail | montessori school |
| mortgage banker | mossaic work | motel |
| motion pictures | motion picture theaters | motorcycle |
| motorcycle dealers | motor home | motor scooter dealers |
| motor scooters | motor vehicle | motor vehicle accessories |
| motor vehicle new parts | motor vehicle parts | motor vehicle supplies |
| movie theaters | moving supplies | moving supplies renting |
| muffins | mufflers engine | museum |
| musical instruments | music school |
