Pedestrians walk past a branch of Postal Savings Bank of China in Yichang city, central China's Hubei province, January 7, 2015. [Photo/IC]

Postal Savings Bank of China Co, moving closer to the world's biggest share sale this year, will seek listing approval this week for a Hong Kong initial public offering that could raise about $8 billion, people with knowledge of the matter said.

The Beijing-based bank plans to seek approval from the Hong Kong bourse on Aug 25, according to the people, who asked not to be identified as the information is private.

The bank, which has more outlets than any listed lender, aims to list as early as September, people with knowledge of the matter said earlier.

Postal Savings Bank, ubiquitous in small-town China, joins Bank of Tianjin Co and China Zheshang Bank Co in selling shares in Hong Kong to fund expansion.

It reported an 11 percent increase in first-quarter profit as it pared provisions for bad loans, according to prelisting documents filed with the Hong Kong exchange.

A Hong Kong-based external spokeswoman for Postal Savings Bank declined to comment.

The lender has also plunged into shadow-banking arrangements that could make investors question its reputation as sleepy and safe.

Postal Savings Bank's prelisting documents disclosed 953 billion yuan ($144 billion) of interbank investments in "special purpose vehicles", which can include holdings of wealth management products, trust investment plans, asset management plans and securities investment funds. The holdings are up more than 500 percent since 2013.

Chinese financial companies that listed in the city this year have gained an average 1.1 percent from their offer prices when adjusted for deal size, according to data compiled by Bloomberg.

Hong Kong first-time share sales have raised $9.7 billion in 2016, down from $20.1 billion for the same period last year, the data showed.

Bloomberg