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Thailand's king, who died Thursday, was reputed to be the world's richest royal and one of the wealthiest people on the planet.

It was a status that clashed with the carefully managed image of a monarch intensely concerned for his people's welfare and one that Thai authorities were always anxious to correct.

But try as officials might, there was no escaping that Thailand's monarchy, embodied for 70 years by King Bhumibol Adulyadej, was a fabulously wealthy institution in a country where the widening gap between an affluent Bangkok and a poor but well populated countryside fueled years of political conflict.

In 2011, American rich-list publisher Forbes tallied up the holdings of the Crown Property Bureau that answers to the Thai monarch and estimated Bhumibol's wealth at more than $30 billion. It owed much to research several years earlier by Thai economist Porphant Ouyyant that made plain the enormous financial clout of the secretive bureau.

The Forbes listicle earned a written rebuke from the Thai Embassy in Washington, which emphasized that the royal assets held by the bureau are not the king's personal property, but belong to the institution of the monarchy and are "held in trust for the nation."

That distinction is enshrined in Thai law, as is the tax-exempt status of the bureau, which has estimated revenue of $2.5 billion to $3 billion a year, from which part of the royal family's expenses are paid.

With extensive holdings of land including prime real estate in Bangkok and stakes in two of the country's biggest companies, the bureau is a formidable player in the Thai economy, if not the most powerful. By now, its value is likely many more billons higher than the 2011 estimate.

Some of the details are easy to establish but others are subject to much speculation and debate because of the veil the bureau has long operated under. Nowadays it produces a glossy annual report that reveals little of substance.

A 21 percent stake in the stock market-listed Siam Commercial Bank is currently worth about $2.9 billion and a 31 percent stake in building materials conglomerate Siam Cement is worth $5.2 billion. Much of the rest of its wealth comes from ownership of land including extensive prime real estate in Bangkok on which sits some of the best known malls and hotels in Asia. It also owns an insurer, Dewes, and stakes in other businesses including majority ownership of luxury hotel owner Kempinski.

A semi-official biography of Bhumibol published in 2011 devotes a chapter to the bureau, which effectively endorsed it as fact by publishing the chapter on the bureau website.

Property holdings cover 3,320 acres in Bangkok and more than 13,000 acres in the rest of the country, with some 40,000 rental contracts, according to the chapter. It says a high estimate of the value of the Bangkok property alone is 1 trillion baht ($28 billion) but the bureau values it at less than a third of that. Many of the rents it charges are far below market rates.

The roots of the Thai monarchy's enormous wealth lie in the privilege and power enjoyed in the pre-1932 era of absolute kingship.

The Crown Property Bureau's predecessor was the Privy Purse Bureau, which consumed 15 percent of government revenue and under the modernizing King Chulalongkorn branched out into buying property, initially for palaces for his prodigiously large family and shophouses to accommodate an influx of Chinese into Bangkok, according to the biography. Its claim on the public purse was also used to fund enterprises that would later become the Siam Commercial Bank and Siam Cement, two of Thailand's largest companies.

Thailand's monarchy languished after the absolute monarchy was overthrown by a coup in 1932 but a revival of its prestige under Bhumibol was intertwined with the expanding commercial success of the property bureau.