HONG KONG, Oct. 10 — Zhu Xiaohua, the former president of China's sixth-largest bank and previously one of China's leading financial officials, was convicted today in Beijing on bribery charges and sentenced to 15 years in prison. The verdict, reported by the official New China News Agency, was the latest sign of Beijing's increasingly tough stance in cases of possible corporate malfeasance. Mr. Zhu is the highest-ranking banker convicted so far in the Chinese government's move against executives at state-owned banks. Some have made huge loans to close friends — poor credit risks who are also sometimes the sources of...