| abortion clinics | abrasive products | accommodation |
| accountant | accounting | accounting equipment |
| accounting general services | accounting services | acting school |
| acupuncture clinic | adhesive manufacturer | adjustment services |
| adm-communications | adm-communications utilities | administration of educational programs |
| administration of general economic programs | administration of manpower programs | administration of public health programs |
| administration of social programs | administration of transportation | administration of veterans' affairs |
| adoption attorneys | advertising | advertising-computer |
| advertising-outdoor | advertising-promotional | advertising agencies |
| advertising counselors | advertising specialties | after school |
| after school care | after school programs | air cargo services |
| air compressor | air conditioning | air conditioning supplies |
| air courier service | aircraft | aircraft dealers |
| aircraft equipment parts | aircraft equipment supplies | aircraft manufacturers |
| airline companies | airline services | airport |
| airport supply | alcoholic beverage | ale |
| alley | allied garments | allied products |
| allied services | aluminum die casting | aluminum die castings manufacturers |
| aluminum drawing | aluminum extruded products | aluminum extruded products manufacturers |
| aluminum foundry | aluminum rolling | amusement |
| amusement parks | analytical instruments | animal clinic |
| animal doctor | animal health | animal hospital |
| animal specialty services | ankle surgeons | antique jewelry |
| apartment building operators | apparel-belts | apparel manufacturer |
| apparel trimmings | appliance dealers | appliances repairing |
| architects | architectural metalwork | architectural services |
| armored car service | art gallery | artists fine arts |
| art school | athletic goods | athletic organizations |
| attorney | auditing | auto cleaning detailing |
| auto dealers | auto detailing | automation equipment |
| automation equipment manufacturers | automation system | automation systems manufacturers |
| automobile | automobile body | automobile body painting |
| automobile body repairing | automobile dealers | automobile detail |
| automobile detail up service | automobile parking | automobile parts manufacturers |
| automobile parts rebuilt | automobile supplies manufacturers | automotive glass replacement shops |
| automotive repair shop | automotive stamping | automotive transmission repair shops |
| automotive trimming | auto polishing | auto supply stores |
| auto transmissions | auto washing polishing |
