Net worth: $35 billion
The world's longest-reigning monarch is revered as a deity. His Crown Property Bureau, through which he holds wealth, granted unprecedented access this year, revealing vast landholdings, including 3,493 acres in Bangkok. He also owns stakes in the publicly listed Siam Cement and Siam Commercial Bank. He recently increased investment in Deves Insurance in order to take it private. While the crown remains technically separate from state, the king exerts enormous influence and is thought to have given his implicit blessing to the 2006 coup that overthrew former prime minister Thaksin Shinawatra.
No. 2: Sheikh Khalifa bin Zayed Al Nahyan (United Arab Emirates) Age: 60
Net worth: $23 billion
President of the UAE and hereditary ruler of its capital emirate, Abu Dhabi. UAE is home to one-tenth of world's oil reserves; petrodollars-dollars are the president's family's original source of wealth. His real estate also is becoming more valuable, as property values rose 100% from 2005 to 2007. Sheikh Khalifa spent more than $1 billion--including $200 million on a Frank Gehry-designed Guggenheim museum--on branding Abu Dhabi as a cultural center. Abu Dhabi Investment Authority recently made headlines by investing $7.5 billion in Citibank and buying New York's Chrysler Building for $800 million.
No. 3: King Abdullah bin Abdul Aziz (Saudi Arabia) Age: 84
Net worth: $21 billion
Ascended to the throne August 2005; soon after, construction began on a $26 billion city named in his honor, which the government hopes will become the new economic epicenter of the Middle East. Saudi Arabia is now earning approximately $1 billion a day from oil exports, helping boost the royal family's fortune. The king is an avid horseman and breeds Arabian horses; he founded the Equestrian Club in Riyadh.
No. 4: Sultan Haji Hassanal Bolkiah (Brunei) Age: 62
Net worth: $20 billion
Crowned 40 years ago after his father's voluntary abdication, the 29th sultan of Brunei is heir to an unbroken 600-year-old Muslim dynasty and rules concurrently as its prime minister, defense minister, finance minister and head of religion. The sultan's wealth is based on oil and gas reserves, but with oil fields set to dry up in 10 years, production has been cut. He is currently battling with brother Prince Jefri over allegedly misappropriated assets; an arrest warrant was issued for Prince Jefri this summer when he reportedly failed to appear in a U.K. court to address charges.
No. 5: Sheikh Mohammed bin Rashid Al Maktoum (Dubai) Age: 58
Net worth: $18 billion
Ruler of Dubai, an emirate of the UAE. Sheikh Mohammed is a majority shareholder of Dubai Holding, a conglomerate with stakes in HSBC Holdings and Sony, as well as real estate holdings, including New York's Essex House Hotel. A formidable figure in horse racing, he owns a 3,800-acre farm in Kentucky and bought Australia's Ingham stud farm for reported $460 million. Dubai's sovereign wealth fun recently paid $5 billion for a piece of MGM Mirage and $825 million to purchase retailer Barneys New York outright.
No. 7: Sheikh Hamad bin Khalifa Al Thani (Qatar) Age: 56
Net worth: $2 billion
Became ruler after deposing his father in a bloodless coup in 1995. Sheikh Hamad spearheaded the development of Qatar's vast oil and natural gas reserves. He is currently making money from LNG commissions, with contracts with Korea, Belgium and Taiwan. The country now has the highest per-capita income in the world. A graduate of Britain's Sandhurst Military Academy, Sheikh Hamad also oversaw the modernization of Qatar's armed forces. Provided key start-up capital for Al Jazeera and its English sister station.
No. 8: King Mohammed VI (Morocco) Age: 46
Net worth: $1.5 billion
Ascended to the throne in 1999. Wealth derives from phosphate mining, agriculture and stake in Morocco's largest public company ONA. Morocco's economic growth has slowed to 2% in the face of a serious drought, putting a serious dent in the royal fortune. Still, palaces reported to have an operating budget of almost $1 million a day. The king is making an effort to alleviate poverty and improve human rights. Last April, he pardoned eight Moroccan activists imprisoned for chanting anti-monarchy slogans.
No. 9: Prince Albert II (Monaco) Age: 50
Net worth: $1.4 billion
Took over 700-year Grimaldi-family reign of Monaco in 2005. Inherited a fortune that includes real estate, art, antique cars, stamps and a stake in Monte Carlo's casino, Soci?t? des Bains de Mer. An environmentalist, Prince Albert drives a hybrid car and has pushed for CO-2 reduction, but a controversial expansion of Monaco, with plans to build a new district on the sea (apparently to be erected on giant pillars), has opponents claiming the project would create an underwater desert. The eligible bachelor is reportedly sending girlfriend to French immersion classes.
No. 10: Sultan Qaboos bin Said (Oman) Age: 67
Net worth: $1.1 billion
Assumed the throne in 1970 after overthrowing his father, who had kept the prince under house arrest for six years. His fortune is up this year, thanks to an oil surplus; he is investing part of the surplus in tourism. The divorced sultan has donated millions to restore Oman's mosques and is a classical music fan. He reportedly owns a 500-foot yacht.
No. 12: Queen Elizabeth II (U.K.) Age: 82
Net worth: $650 million
The oldest living monarch in British history, Elizabeth II ascended the throne at age 25 and plans to keep ruling until she's physically unable, thwarting hopes of her son, Charles, to be king soon. Her personal fortune is based on property in England and Scotland, fine art, gems and a stamp collection built by her grandfather. Buckingham Palace and the Crown Jewels do not figure in, as they are state-owned treasures. Her penchant for Welsh corgis is overshadowed only by her love of horses.
No. 13: Sheikh Sabah Al-Ahmad Al-Jaber Al-Sabah (Kuwait) Age: 79
Net worth: $500 million
The country's longtime foreign minister was not originally in line to throne; in 2006, he was appointed by the National Assembly after the crown prince was deemed too ill to rule. Unlike royals in many Gulf states, Sheikh Sabah's wealth is based on a stipend. He called for new elections after the resignation of Kuwaiti cabinet in March and is promoting economic reform to attract more investment, speed up privatization and ease land-ownership regulations to prepare for the post-oil era.
No. 14: Queen Beatrix Wilhelmina Armgard (Netherlands) Age: 70
Net worth: $300 million
Rumored to be considering stepping down so that her eldest son, Willem-Alexander, can ascend the throne, which would make him the first Dutch king in more than a century. The fortune of Beatrix and her family has been hit by a declining Dutch equities market, though their real estate holdings, such as Castle Drakensteyn and land in Tavernelle, have appreciated with the overall market.
No. 15: King Mswati III (Swaziland) Age: 40
Net worth: $200 million
Sub-Saharan Africa's last absolute monarch dissolved Parliament in June, with confusion over whether 2005 constitution even allows opposition parties elections have yet to be set. King Mswati assumed throne at age 18; his wealth derives from investments and real estate. The king spent a reported $2.5 million celebrating 40 years of country's independence, along with his 40th birthday. His lavish lifestyle is highlighted in the documentary film Without the King.