June 30 (Reuters) - Assets at the Exchange Fund, which is used to back the Hong Kong dollar, totalled HK$3,807.4 billion ($487.81 billion) at the end of May, the Hong Kong Monetary Authority (HKMA) said on Friday.
The figure was HK$23.6 billion lower than the total at the end of April, with foreign currency assets and Hong Kong dollar assets falling HK$14.7 billion and HK$8.9 billion respectively, the city's de facto central bank said in a statement.
The HKMA said the decline in foreign currency assets was mainly due to a decrease in unsettled purchases of securities, which was partly offset by mark-to-market gains on foreign currency portfolios and the purchase of foreign currencies with Hong Kong dollars.
The decline in Hong Kong dollar assets was mainly due to withdrawals of placements by Fiscal Reserves and sale of Hong Kong dollars for foreign currencies, which were partly offset by the increase in market value of Hong Kong equities.
$1 = 7.8051 Hong Kong dollars Reporting by Twinnie Siu in HONG KONG; Editing by Sunil Nair