| 3720 | Anti-friction metal manufacturing | |
| 2302 | Antimony mining | |
| 3720 | Antimony refining | |
| 3320 | Antique furniture restoration | |
| 3851 | Antiseptic dressing manufacturing | |
| 8310 | Apartment house operation | |
| 2902 | Apatite mining | |
| 2901 | Aplite mining or quarrying | |
| 3825 | Apothecary scale manufacturing | |
| 3220 | Apparel belt, all material, cutting and sewing | |
| 9520 | Apparel cleaning | |
| 9520 | Apparel dyeing | |
| 8330 | Apparel manufacturing machinery rental service | |
| 9520 | Apparel pressing | |
| 6200 | Apparel renting, except supply of laundered clothing on contract basis | |
| 9520 | Apparel repairing | |
| 3220 | Apparel scarf cutting and sewing | |
| 9512 | Appliance, household electric, repairing | |
| 8329 | Appraiser, except real estate or insurance | |
| 3220 | Apron, except rubber and sanitary, manufacturing | |
| 1302 | Aquarium fish breeding | |
| 5000 | Aqueduct construction | |
| 9100 | Arbitration and conciliation service, governmental | |
| 3823 | Arbor, machine tool accessory, manufacturing | |
| 3839 | Arc lamp, except therapeutic, manufacturing | |
| 3851 | Arch support manufacturing | |
| 3311 | Arch, wooden, for building purpose, manufacturing | |
| 3903 | Archery target manufacturing | |
| 8324 | Architect, own account | |
| 3813 | Architectural metal work manufacturing | |
| 3691 | Architectural terracotta manufacturing | |
| 9490 | Arena operation | |
| 2901 | Argillite quarrying | |
| 3132 | Argol, by-product of wine industries | |
| 3831 | Armature manufacturing | |
| 3831 | Armature winding and repairing | |
| 3710 | Armour plate manufacturing | |
| 3839 | Armoured cable manufacturing | |
| 3843 | Armoured car manufacturing | |
| 3829 | Arms, including accessories, manufacturing | |