The oil and gas industry in Canada, as in other regions, is generally divided into three main segments: upstream, midstream, and downstream. Upstream companies engage in the exploration and production (E&P) of crude oil and natural gas, which entails searching for oil below the ground and drilling wells in order to access those reserves. In some cases, such as in the Canadian oil sands, companies either mine for crude bitumen, a dense, viscous form of crude oil, or use in-situ recovery processes that inject steam and chemicals deep beneath the ground to separate the bitumen from the sand and pump it to the surface. Both methods are relatively expensive compared to traditional well-extraction methods, making the break-even price of oil for oil-sand producers much higher than for more traditional producers. Midstream companies are engaged in the storage and transportation of oil and gas, while downstream companies refine and sell finished petroleum products.

Here are the top 10 biggest Canadian oil and gas companies measured by 12-month trailing (TTM) revenue. All figures are as of March 30, 2020.

Enbridge Inc. (ENB.TO)

  • Revenue (TTM): CA$50.1 billion
  • Net Income (TTM): CA$5.7 billion
  • Market Cap: CA$78.7 billion
  • 1-Year Trailing Total Return: -16.0%
  • PE Ratio (TTM): 14.8

Enbridge is an energy infrastructure company that provides energy transportation, distribution, and related services. The company operates a network of crude oil, liquids, and natural gas pipelines, as well as regulated natural gas distribution utilities. Enbridge also invests in renewable energy assets and transmission facilities.

Suncor Energy Inc. (SU.TO)

  • Revenue (TTM): CA$38.3 billion
  • Net Income (TTM): CA$2.9 billion
  • Market Cap: CA$25.1 billion
  • 1-Year Trailing Total Return: -60.5%
  • PE Ratio (TTM): 9.0

Suncor Energy is an integrated energy company focused on developing petroleum resource basins in Canada's Athabasca oil sands. The company is engaged in the exploration, acquisition, development, production, refining, transportation, and marketing of crude oil.

Imperial Oil Ltd. (IMO.TO)

  • Revenue (TTM): CA$34.0 billion
  • Net Income (TTM): CA$2.2 billion
  • Market Cap: CA$9.8 billion
  • 1-Year Trailing Total Return: -62.0%
  • PE Ratio (TTM): 4.6

Imperial Oil is an integrated company engaged in the exploration, production, refining, transportation, and sale of crude oil and natural gas. The company also manufactures and markets various petrochemicals.

Canadian Natural Resources Ltd. (CNQ.TO)

  • Revenue (TTM): CA$24.4 billion
  • Net Income (TTM): CA$5.4 billion
  • Market Cap: CA$15.7 billion
  • 1-Year Trailing Total Return: -60.8%
  • PE Ratio (TTM): 2.9

Canadian Natural Resources is an oil and gas exploration and production company. It produces synthetic crude oil, light and medium crude oil, bitumen, primary heavy crude oil, and Pelican Lake heavy crude oil.

Cenovus Energy Inc. (CVE.TO)

  • Revenue (TTM): CA$21.4 billion
  • Net Income (TTM): CA$2.2 billion
  • Market Cap: CA$2.9 billion
  • 1-Year Trailing Total Return: -79.0%
  • PE Ratio (TTM): 1.3

Cenovus Energy is an integrated oil and natural gas company engaged in the development, production, and marketing of crude oil, natural gas liquids, and natural gas. It also refines crude oil and transports and sells refined petroleum and chemical products.

Husky Energy Inc. (HSE.TO)

  • Revenue (TTM): CA$20.3 billion
  • Net Income (TTM): -CA$1.4 billion
  • Market Cap: CA$3.2 billion
  • 1-Year Trailing Total Return: -73.8%
  • PE Ratio (TTM): N/A

Husky Energy is an integrated company engaged in the exploration, development, production, transportation, storage, and marketing of crude oil, natural gas, and natural gas liquids. The company also refines crude oil and markets refined petroleum products.

Parkland Fuel Corp. (PKI.TO)

  • Revenue (TTM): CA$18.5 billion
  • Net Income (TTM): CA$402.0 million
  • Market Cap: CA$3.6 billion
  • 1-Year Trailing Total Return: -37.7%
  • PE Ratio (TTM): 9.5

Parkland Fuel is an energy supplier engaged in the marketing and distribution of a variety of petroleum products including gasoline, diesel, propane, lubricants, heating oil, and more. The company supplies and supports a network of retail gas stations, and offers its products to a range of commercial, industrial, and residential customers.

TC Energy Corp. (TRP.TO)

  • Revenue (TTM): CA$13.3 billion
  • Net Income (TTM): CA$4.1 billion
  • Market Cap: CA$54.7 billion
  • 1-Year Trailing Total Return: 0.4%
  • PE Ratio (TTM): 13.6

TC Energy is an energy infrastructure company that builds and operates a network of natural gas pipelines, which transports natural gas from supply basins to local distribution companies, power generation plants, industrial facilities, and other customers. The company also owns regulated natural gas storage facilities and power generation facilities. TC Energy announced earlier this month that it has executed an exclusive letter of intent to purchase the Pioneer Pipeline for $255 million.

Gibson Energy Inc. (GEI.TO)

  • Revenue (TTM): CA$7.3 billion
  • Net Income (TTM): CA$182.9 million
  • Market Cap: CA$2.3 billion
  • 1-Year Trailing Total Return: -29.8%
  • PE Ratio (TTM): 12.6

Gibson Energy is an integrated service provider to the oil and gas industry. The company engages in the transportation, storage, blending, processing, marketing, and distribution of crude oil, condensate, natural gas liquids, water, oilfield waste, and refined products. The company owns a network of terminals, pipelines, and storage tanks.

Pembina Pipeline Corp. (PPL.TO)

  • Revenue (TTM): CA$7.2 billion
  • Net Income (TTM): CA$1.5 billion
  • Market Cap: CA$13.2 billion
  • 1-Year Trailing Total Return: -48.2%
  • PE Ratio (TTM): 9.1

Pembina Pipeline provides transportation and midstream services for the energy industry. The company operates conventional and oil-sands pipelines, stores oil, and gathers and processes natural gas.