A unit of the insurer, Ping An Asset Management Co, bought 10.8 million shares at an average price of HK$28.29 (£2.90, $3.70) per share.
It comes as British and US lawmakers criticised, HSBC and Standard Chartered (STAN.L) for supporting China’s national security law for Hong Kong, following Beijing’s handling of the pro-democracy movement in the territory.
The national security law criminalises criticism of the Chinese Communist party.
At the time, chief executive Noel Quinn, said: “We will face any political challenges that arise with a focus on the long-term needs of our customers and the best interests of our investors.”
Both banks, which are dual listed in London (^FTSE) and Hong Kong (0388.HK) make most of their sales in Asia, while HSBC is Europe’s largest bank by assets, the bank generates around half of its revenue in Asia.
Before the latest transaction, Ping An held a 7.95% share in the bank, according to a Hong Kong stock exchange filing on Friday.
In 2018, after gradually buying more shares in HSBC, Ping An overtook Black Rock Inc (BLK), which currently owns the second biggest stake with a 7.14% share.
In August, the Asia-focused bank announced the COVID-19 pandemic and worsening tensions between the US and China dealt a double blow to HSBC during the first half of its financial year, with pre-tax profits plunging 65% to $4.3bn.
HSBC said that while its financial performance will continue to be affected by the coronavirus crisis, geopolitical uncertainty “could also weigh heavily” on its clients.
Quinn cited tensions between China and both the US and UK, as well as the UK’s post-Brexit trading relationship with the European Union as factors.