The Brunei Investment Agency (BIA) mostly functions as the country’s central bank, managing Brunei’s General Reserve Fund and other external assets. All funds come from the Ministry of Finance, primarily surplus revenues from Brunei's abundant oil exports. The fund is highly opaque and has been involved in several controversies and governance issues. There is a thin line between the SWF and the Sultan’s wealth, including his brother Prince Bolkiah, who was BIA’s chairman and embezzled USD 16 billion from the fund.