Yagiri Pharmaceuticals

Yagiri Pharmaceuticals is a Japanese company based in Ikebukuro. Namie Yagiri used to be its Chief until it was sold to an American company, Nebula. While she was Chief, Namie had the company kidnap people to perform experiments on them. Namie also used the company to hide Celty's head.

Trivia
Tall guy: 浅沼 - Asanuma
 * According to the "Durarara no Subete', the guys who worked for Yagiri Pharmaceuticals (last names only):

Small guy: 森田 - Morita

Fat guy: 金沢 - Kanazawa