(Bloomberg) -- Mainland Chinese investors snapped up a record amount of Hong Kong stocks as they ramped up exposure to risk assets in the city amid a revival of animal spirits and a weakening yuan.

Traders in Shanghai and Shenzhen bought HK$778 billion ($100 billion) of stocks in the financial hub this year through Dec. 20, the highest annual amount since trading links with the city opened in 2016, according to Bloomberg-compiled data. Shares in Alibaba Group Holding Ltd., Bank of China Ltd. and China Mobile Ltd. were among the most purchased.

Onshore investors boosted their share of trading in the city to a record 45% in the fourth quarter as Beijing’s stimulus blitz propelled benchmark gauges. Other factors leading to the unprecedented southbound buying include a weaker yuan, creating an appetite for dollar assets, said Zeng Wenkai, managing director at Shengqi Asset Management Co.

“The determining factor in how Hong Kong’s market fares going forward lies in the balance between the demand by onshore investors and pressure from outflows by global funds,” said Zeng. In the short term, though, it’s unlikely for Chinese investors to be the biggest holders of the city’s equities, he said.

Onshore traders have bought a cumulative HK$3.3 trillion of Hong Kong shares since the trading link began.

--With assistance from Mengchen Lu.