| C | Energy |
| This industrial sector covers the exploitation of energy-related resources and the production and distribution of fuels or energy. | |
| 10 | Petroleum and Natural Gas |
| This subsector consists of groupings of companies primarily engaged in the extraction and processing of petroleum and natural gas and the distribution of their derivatives. Services incidental to exploration and production of petroleum and natural gas are also covered here. | |
| 101 | Petroleum and Natural Gas Exploration and Extraction |
| 1011 | Petroleum and Natural Gas Exploration and Extraction |
| Companies primarily engaged in the exploration for, and production of, crude oil and natural gas whether by conventional or non-conventional methods. | |
| 102 | Natural Gas Distribution |
| Companies primarily engaged in wholesaling or the combined wholesaling and retailing of natural gas. | |
| 1021 | Natural Gas Wholesaling |
| Companies primarily engaged in wholesaling natural gas. Covered here is the related transportation of natural gas by pipelines or other means from the gas fields to local distributors. | |
| 1022 | Natural Gas, Combined Wholesaling and Retailing |
| Companies primarily engaged in the combined wholesaling and retailing of natural gas or synthetic gas. Covered here is the related transportation of natural gas by a system of mains or other means. | |
| 103 | Petroleum Refining and Distributing |
| 1031 | Petroleum Refining and Distributing |
| Companies primarily engaged in the processing of crude petroleum and the distribution of a family of refined petroleum products. Companies primarily engaged in refining only or wholesaling only, are covered here. | |
| 104 | Service Stations |
| 1041 | Service Stations |
| Companies primarily engaged in retailing gasoline and other motor vehicle fuels, lubricating oils and greases. The lubricating of motor vehicles is covered here. Repairing of motor vehicles is covered in 3043 - Motor Vehicle Repair Shops and Related Services. | |
| 105 | Petroleum Extracting, Refining and Distributing, Integrated Operations |
| 1051 | Petroleum Extracting, Refining and Distributing, Integrated Operations |
| Companies primarily engaged in operations which integrate petroleum exploration and production, and the refining and marketing of petroleum products. | |
| 109 | Services Incidental to Petroleum and Natural Gas Production |
| Companies primarily engaged in contract drilling for petroleum and natural gas, petroleum pipeline operations and other services incidental to petroleum and natural gas production. | |
| 1091 | Contract Drilling, Petroleum and Natural Gas |
| Companies primarily engaged in contract drilling for crude oil and natural gas. Specialized services to contract drillers such as rig erecting and maintenance are covered here. | |
| 1092 | Petroleum Pipeline Operations |
| Companies primarily engaged in the pipeline transportation of crude oil or other liquid hydrocarbons. | |
| 1099 | Other Services Incidental to Petroleum and Natural Gas Production |
| Companies primarily engaged in petroleum and natural gas operations services not elsewhere classified. | |
| 11 | Other Fuels |
| This subsector consists of groupings of companies primarily engaged in the extraction, processing and marketing of fuels not elsewhere classified. | |
| 111 | Coal Mining and Distributing |
| 1111 | Coal Mining and Distributing |
| Companies primarily engaged in mining and processing coal and producing coal products. The marketing of coal is covered here. | |
| 112 | Uranium Mining and Refining |
| 1121 | Uranium Mining and Refining |
| Companies primarily engaged in extracting, dressing and beneficiating uranium ores and refining uranium oxides. | |
| 119 | Other Fuels Production and Distribution n.e.c. |
| 1199 | Other Fuels Production and Distribution n.e.c. |
| Companies primarily engaged in producing fuels not elsewhere classified. The marketing of fuelwood is covered here. | |
| 12 | Electricity |
| This subsector consists of groupings of companies primarily engaged in the generation, transmission and distribution of electricity. | |
| 121 | Electricity |
| 1211 | Electricity Generation, Transmission and Distribution |
| Companies primarily engaged in operations which integrate the generation, transmission and distribution of electricity. | |
| 1212 | Electricity Distribution |
| Companies primarily engaged in distributing electricity which they have purchased. | |