A village official (center) inquires about loan services with two bank employees at a Postal Savings Bank of China Co branch in Fengxin county, Jiangxi province. [Photo/Xinhua]

The Postal Savings Bank of China Co filed a listing application with the Hong Kong stock exchange, people with knowledge of the matter said, as it prepares for an $8 billion initial public offering that could be the world's biggest this year.

The bank, which has the most branches of any Chinese lender, aims to list as early as September, two people said on Thursday, asking not to be identified as the information is private. An $8 billion IPO would be the largest since e-commerce billionaire Jack Ma's Alibaba Group Holding Ltd priced its $25 billion New York share sale in September 2014, according to data compiled by Bloomberg.

Postal Savings Bank is seeking to list at one of the most turbulent times for investors in years. Britain's vote to exit the European Union roiled global equity markets and caused the pound to plunge to its lowest in more than 30 years. The amount raised from first-time share sales globally was $52.3 billion in the first half, the slowest pace in seven years, Bloomberg-compiled data show.

A Hong Kong-based external spokeswoman for the Postal Savings Bank declined to comment. IFR reported the submission earlier Thursday in Hong Kong, citing unidentified people.

Postal Savings Bank hired Bank of America Corp, China International Capital Corp, Goldman Sachs Group Inc, JPMorgan Chase & Co and Morgan Stanley to arrange the sale, people with knowledge of the matter said in January.

The lender raised 45 billion yuan ($6.8 billion) in December selling a 17 percent stake to investors including the Canada Pension Plan Investment Board, Singapore state investment company Temasek Holdings Pte and UBS Group AG.