Opel Automobile GmbH, usually shortened to Opel, is a German automobile manufacturer which has been a subsidiary of Stellantis since 16 January 2021. It was owned by the American automaker General Motors from 1929 until 2017 and the PSA Group prior to its merger with Fiat Chrysler Automobiles to form Stellantis in 2021. Most of the Opel lineup is marketed under the Vauxhall Motors brand in the United Kingdom since the 1980s. Some Opel vehicles were badge-engineered in Australia under the Holden brand until 2020, in North America and China under the Buick, Saturn, and Cadillac brands, and in South America under the Chevrolet brand.

Buick is a division of the American automobile manufacturer General Motors (GM). Started by automotive pioneer David Dunbar Buick in 1899, it was among the first American automobile brands and was the company that established General Motors in 1908. Before the establishment of General Motors, GM founder William C. Durant had served as Buick's general manager and major investor. With the demise of Oldsmobile in 2004, Buick became the oldest surviving American carmaker.