The Postal Savings Bank of China, or PSBC, has started trading on the Hong Kong stock exchange. 

The listing is set to raise 7.4 billion US dollars in its initial public offering, making it the world's biggest flotation this year. PSBC is China's fifth-largest lender with 40,000 branches -- more than any other bank in the country.

Founded in 2007, it provides basic banking services to farmers and agricultural business owners. With a presence in around 70 percent of China's rural areas, the bank is the only financial institution present in some of the country's most remote regions.