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.