When did Xinhua Distribution Group become a state-owned enterprise?

In 2004.

In September 2004, Shanghai Xinhua Distribution Group was transformed from a wholly state-owned enterprise into a diversified state-owned enterprise through the allocation of state-owned assets.

Headquartered in Sichuan, Xinhua Publishing Group Co., Ltd., formerly known as Sichuan Xinhua Bookstore Group Co., Ltd., was established in March 2000. It is formed by the reorganization of assets of Sichuan Xinhua Bookstore, Sichuan Foreign Language Bookstore and Sichuan Publishing Foreign Trade Company.