China's anti-corruption campaign is spreading to the country's financial sector following the arrest of two senior bank officials in recent days.
Financial elites had been largely immune from the sweeping anti-corruption campaign that has claimed hundreds of scalps within the government, military and state-owned energy companies.
But the recent arrests of bankers appear to be targeting patronage networks linked to specific political figures, rather than signalling a broader crackdown on the financial sector.
Bank of Beijing said on Monday night that board member Lu Haijun was under investigation for "suspected serious violations of discipline" — the standard euphemism in China for official corruption.
The probe into Mr Lu follows the arrest of Minsheng Bank president Mao Xiaofeng in an investigation linked to a top aide to former president Hu Jintao.
Apart from government, Communist party and military officials, corporate executives from the energy sector have been the most frequent targets of the sweeping anti-corruption campaign.
The most senior leader to face formal corruption charges since the founding of the People's Republic in 1949 is former security tsar Zhou Yongkang, who rose through the ranks of state oil company China National Petroleum Corp and counted the energy sector as a key power base.
The probe into Mr Lu, who served on Bank of Beijing's board as a representative of Beijing Energy Investment Holding, may also be linked to Mr Zhou. Mr Lu was formerly chairman of Beijing Energy Investment, a major shareholder in Bank of Beijing. He had previously chaired a string of other energy companies. Mr Lu could not be reached for comment.
The turn towards the financial system also appears to be linked to probes into Mr Hu's former aide Ling Jihua and spymaster Ma Jian.
Founder Securities, China's ninth-largest brokerage by assets, said last month it had lost contact with chairman Lei Jie. A battle has raged in recent months between the brokerage's parent, technology and finance conglomerate Founder Group, and property developer Beijing Zenith Holdings.
Zenith said that Founder is linked to Mr Ling, while respected Chinese financial magazine Caixin quotes sources linking Zenith to Mr Ma.
In a series of postings on its official Weibo account, Zenith accused Founder Group executives of financial crimes including insider trading, market manipulation and illegally selling state assets.
Founder has denied the allegations. The disappearance of Mr Lei came days after the chairman and three top executives of Founder Group were ordered to co-operate with an official investigation and were replaced.
Apart from arrests targeting specific politicians, signs of broader anti-corruption efforts in financial markets began to emerge in 2013 when the securities regulator targeted bond fund managers for profit-skimming and insider dealing.
Last year the regulator shifted its focus to insider trading in the stockmarket, targeting a practice known as "rat trading" in which fund managers buy shares for their personal accounts, then sell at a profit after purchases from the funds they manage boosted the stock price.
People's Daily, the official Communist party newspaper, reported last March that the Central Commission on Discipline Inspection, the party's anti-corruption organ, had reorganised itself, establishing a division focused on financial institutions.
Wang Qishan, who heads the CCDI and ranks sixth in the elite seven-man Politburo Standing Committee, is familiar with the financial sector, having served as deputy central bank governor and president of China Construction Bank in the 1990s. From 2008 to 2013 he was vice-premier for financial and commercial affairs under then-prime minister Wen Jiabao.
On Friday the China Securities Regulatory Commission said it would punish the country's largest fund management company and four others for insider trading.