Nintendo is the branding company and creator of Donkey Kong and many other popular video game series such as Pokémon and Super Mario.
Nintendo has been the publisher of every single Donkey Kong game up to the present. The company originally started out making card games, being very successful. Soon enough, they went on to make video games, getting a very big hit in the original Donkey Kong arcade. From that point on, it used its success in that game to build the foundation for other series, including the aforementioned Pokémon and Mario series, the latter being based on characters in Donkey Kong itself. In fact, Nintendo remains one of the top video game companies in the market today.