BANGKOK—Thailand’s crown prince won’t only succeed his father as king. He will also inherit the keys to one of the world’s largest royal fortunes.

The multibillion-dollar wealth of the Thai crown is rarely discussed in the country. Strict lèse-majesté laws, which criminalize any criticism of the monarchy, make many reluctant to study or debate the matter, especially now, just a month after the on Oct. 13.

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