March 31 (Reuters) - Assets at the Exchange Fund, which is used to back the Hong Kong dollar, totalled HK$3,825.0 billion ($492.29 billion) at the end of February, the Hong Kong Monetary Authority (HKMA) said on Friday.
The figure was HK$48.9 billion higher than the total at the end of January, with foreign currency assets and Hong Kong dollar assets rising HK$41.7 billion and HK$7.2 billion respectively, the city's de facto central bank said in a statement.
The HKMA said the rise in foreign currency assets was mainly due to mark-to-market gains on foreign currency portfolios, the purchase of foreign currencies with Hong Kong dollars and an increase in unsettled purchase of securities.
These increases were partly offset by the redemption of certificates of indebtedness.
The rise in Hong Kong dollar assets was mainly due to the increase in exchange fund bills and notes issued but not yet settled, which was partly offset by the sale of Hong Kong dollars for foreign currencies.
$1 = 7.7698 Hong Kong dollars Reporting by Twinnie Siu in HONG KONG; Editing by Biju Dwarakanath