Saudi Prince Al-Waleed Bin Talal is commonly referred to as the richest man in the Middle East. Forbes currently pegs his net worth at $21.2 billion, while Bloomberg's Billionaires Index says it's closer to $32.7 billion.

But who cares about that difference, anyway? What's a few billion to the world's richest?

It turns out that in the case of Prince Al-Waleed, it's a big deal. In 2013, Forbes began pushing Al-Waleed's people for more transparency with regard to the underlying businesses representing his vast fortune. When Al-Waleed was displeased with his overall ranking and Forbes' valuation methods, he filed a libel suit against Forbes in London.

To find out how Prince Al-Waleed accumulated his vast fortune (hint: it isn't family money or oil), and why he's so upset about the Forbes ranking, check out the following slideshow.

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Brian Stoffel has no position in any stocks mentioned. The Motley Fool recommends Twitter and owns shares of Citigroup. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.