Together with certificates of deposits (CD) denominated in yuan, the offshore pool reached 720.2 billion yuan at the end of 2012, up 9 percent from a year earlier, the city's de facto central bank said in a filing submitted to the Legislative Council.
More than 29,000 accounts were opened by non-resident personal customers, with yuan deposits exceeding 4 billion yuan at the end of 2012, compared to 800 million yuan at the end of September.
Hong Kong was previously at a disadvantage before non-resident business was allowed in August, losing out on yuan flows from foreign retail investors to financial centres in Singapore and London, which have no such restrictions.
The filing also showed offshore yuan lending expanded significantly over the past year, with outstanding yuan loans amounting to 79 billion yuan at the end of 2012, up 157 percent from a year earlier.
China kicked off its cross-border yuan loan scheme in Qianhai on Monday with Hong Kong-based banks signing some 2 billion yuan in lending to mainland Chinese firms for 26 projects, in a move which will further boost Hong Kong's yuan loan business.
In 2012, yuan trade settlement handled by banks in Hong Kong amounted to 2,630 billion yuan, increasing 37 percent from 2011 and accounting for about 90 percent of all yuan trade settlement. Meanwhile, payment flows to and from the mainland were largely balanced.
China started the yuan trade settlement scheme in 2009, aiming to promote the international use of its currency. It now takes up about 12 percent of China's trade volumes in total.