500 Rials

The 500 Rials was introduced following the monetary reunification that came after Yemen's bloody 1994 civil war, in which the southern secessionist movement was crushed by Sana'a forces within months. A unified currency was politically necessary — the north and south had maintained separate banking systems since the 1990 merger, and the rial itself had suffered severe depreciation during the conflict.

Thomas De La Rue's involvement brought the note in line with the broader series the bank was standardizing through the mid-1990s. The security package is modest for the denomination — watermark and thread only, with no optically variable elements.