500 Ringgit

Brunei's Currency and Monetary Board operates under a 1967 Currency Interchangeability Agreement with Singapore, meaning Brunei dollar notes are accepted at par in Singapore and vice versa — an arrangement that has survived both countries' separate monetary policies for over five decades. The 500 Ringgit sits at the high end of a series that saw relatively limited street circulation given Brunei's small population and oil-dependent economy where large transactions were typically settled through banking channels rather than physical notes.

Thomas De La Rue's contract for Brunei notes during this period covered multiple denominations printed to a consistent specification. The watermark remains the primary security feature — notably modest by the standards De La Rue was applying to other clients' high-value paper at the same time.