4. Bhumibol Adulyadej – $30 Billion
Bhumibol Adulyadej was the former King of Thailand prior to his death and had been since 1946, which made him one of the longest reigning head of state and Monarch in Thai history at more than 70 years. Over his career as a politician, he was served by a total of 30 Prime Ministers! Adulyadej also managed the Crown Property Bureau, which was valued at over $30 billion, the same as his estimated net worth.