The South African Reserve Bank's (SARB) dollar-denominated holdings of gold and foreign assets fell by US$1.724 billion to US$49.725 billion in September from US$51.449 billion in August, data released by the Reserve Bank on Friday shows.
Net reserves declined $1.195 billion to $47.930 billion from $49.125 billion previously.
Foreign exchange reserves were down $814 million to $40.419 billion, while gold reserves also fell $827 million to $6.514 billion.
The SARB reported its special drawing rights (SDRs) holdings - an interest-bearing international asset created by the IMF allocated in terms of a member's quota, which is based on its relative size in the world economy - at $2.792 billion from $2.876 billion the month before.
The forward position was $6.212 billion from $5.801 in August, while foreign deposits received were at -$8.008 billion from -$8.125 previously.
The SARB said the gross gold and foreign exchange reserves and the international liquidity position (ILP) decreased by $1.7 billion and $1.2 billion respectively at the end of September.
The bank said that during a month of exceptionally high volatility in financial markets, a lower US dollar gold price at month-end resulted in a significant decrease in the value of gold reserves, while the appreciation of the US dollar against other major currencies led to a sizeable downward valuation adjustment in foreign exchange reserves.
The decrease in the ILP, the SARB reported, was due to the decline in gross reserves, whose decline was partially offset by the net increase in the foreign currency deposits received and the forward position.
The latter reflected foreign exchange purchased earlier during the month which were swapped into the forward market, the bank said.