This document lists the names, titles, residences, net worth, and sources of wealth for the five wealthiest royal families in the world as of April 2011. Bhumibol Adulyadej, the King of Thailand, had the highest net worth at $30 billion derived from investments from the Bureau of the Crown Property. Hassanal Bolkiah, the Sultan of Brunei, had the second highest net worth at $20 billion from profits in the oil and gas industry.