Net foreign assets at Saudi Arabia's central bank fell by $7.4 billion to $546.7 billion in September from the previous month, as the government drew down reserves to cover a budget deficit caused by low oil prices, official data showed on Sunday.
Assets shrank by 15.5 percent from a year earlier to their lowest level since January 2012. They reached a record high of $737 billion in August 2014 before starting to fall.
The assets are believed to be mainly denominated in U.S. dollars, in the form of securities such as U.S. Treasury bonds and deposits with banks abroad.
Foreign bank deposits shrank $5.1 billion from the previous month to $114.4 billion in September. Holdings of foreign securities fell $3.5 billion to $372.7 billion.
The government has also been borrowing domestically and abroad to cover part of its deficit, which totalled nearly $100 billion last year. Earlier in October, it raised $17.5 billion in its first international bond issue.
Total deposits at Saudi Arabian commercial banks edged up 0.2 percent from the previous month to 1.58 trillion riyals ($422.0 billion) in September.
Subscribe to Arabian Business' newsletter to receive the latest breaking news and business stories in Dubai,the UAE and the GCC straight to your inbox.