Beijing

THE head of crude oil trading at Chinese state energy giant PetroChina has resigned after 20 years with the company, a rare departure from a state-owned enterprise known for retaining talent in the midst of rapid expansion.

Li Chuang, 42, head of the crude oil department at PetroChina's trading vehicle Chinaoil, resigned in February, having spent the last two years leading a global team of nearly 50 crude oil traders and marketers.