Thailand’s revered King Bhumibol Adulyadej is the world’s richest royal, with a fortune estimated at $US35 billion, according to a Forbes magazine list dominated by Middle Eastern monarchs riding high on surging oil prices.

King Bhumibol, 80 years old and the world’s longest-reigning monarch after six decades on the throne, is regarded as semi-divine by many Thais.

Forbes called it a good year for monarchies, investment-wise. “As a group, the world’s 15 richest royals have increased their total wealth to 131 billion dollars, up from 95 billion last year”. With oil prices soaring, the monarchs of the petro-kingdoms of the Middle East and Asia dominate the list.