We are a leading provider of international crude oil and gas marine transportation services and through our strategic partnership in Teekay Offshore with Brookfield Business Partners L.P. and certain affiliates (collectively, Brookfield) we also offer offshore oil production, storage and offloading services. We generate revenue primarily under long-term, fixed-rate contracts with a diverse customer base of major energy and utility companies. Over the past 15 years, we have undergone a major transformation from being primarily an owner of ships in the cyclical spot tanker business to being an asset manager in the "Marine Midstream" sector. This transformation has included our expansion into the liquefied natural gas (or LNG) and liquefied petroleum gas (or LPG) shipping sectors through our publicly-listed subsidiary Teekay LNG Partners L.P. (NYSE: TGP) (or Teekay LNG), the continuation of our conventional tanker business through our publicly-listed subsidiary Teekay Tankers Ltd. (NYSE: TNK) (or Teekay Tankers), and further growth of our operations in the offshore production, storage and transportation sector through our ownership of TPO AS (formerly TPO Investments AS) and through our equity-accounted investment Teekay Offshore Partners L.P. (NYSE: TOO) (or Teekay Offshore).
The combined Teekay entities operate total assets under management of approximately $16 billion, comprised of approximately 205 liquefied gas, offshore, and conventional tanker assets (excluding vessels managed for third parties). With offices in 14 countries and approximately 8,000 seagoing and shore-based employees, Teekay provides a comprehensive set of marine services to the world's leading oil and gas companies. We are the world's third largest independent LNG carrier owner and operator and one of the world's largest owner and operator of mid-sized crude tankers. Teekay Offshore is the world's largest operator of shuttle tankers and fourth largest independent provider of leased floating production, storage and offloading (or FPSO) unit solutions. Our organizational structure can be divided into (a) our controlling interests in our publicly-listed subsidiaries, Teekay LNG and Teekay Tankers (or the Controlled Daughter Entities), our equity-accounted investment in Teekay Offshore (together with the Controlled Daughter Entities, the Daughter Entities), and (b) Teekay and its remaining subsidiaries, which is referred to herein as Teekay Parent.
Our business strategy across the Teekay Group is focused on the following: