Hu Huaibang worked his way up China's financial sector, moving between regulatory positions and state-owned companies before landing the top job at the Bank of Communications.

In 2013 he became chairman of China Development Bank and held the position until September of last year.

CDB is one of three banks tasked with funding Beijing's pet projects and supporting Chinese companies abroad and has provided massive financing for Xi's signature Belt and Road global infrastructure project.

The bank had $2.3 trillion in total assets at the end of 2018 making it one of the largest lenders in the world, according to its annual report.

It is Hu's connection with fallen Chinese oil tycoon Ye Jianming, chairman of CEFC China Energy, that appears to have landed him in trouble.

CEFC was an upstart energy company that quickly grew to be worth tens of billions of dollars despite a murky track record.

Last year Ye disappeared and is now believed to be held by Chinese authorities for unspecified charges while authorities have begun to sell off parts of the firm.

In Hu's roles at the Bank of Communications and the CDB, he allegedly helped CEFC secure billions in credit lines for its overseas deals.

Hu's alleged involvement in the deals came out in the trial of the fallen party boss of northwest Gansu province who arranged the state support, according to documents and graphics shown by state broadcaster CCTV.

China's anti-graft agency said Wednesday that Hu was suspected of "serious violations of discipline and law", a euphemism that usually means corruption, and was under investigation.

Hu is the latest official to have fallen under suspicion in Xi's campaign against corruption in the Communist Party, which critics have compared to a political purge.