This week, Amazon founder Jeff Bezos saw his net worth soar above $150 billion, giving him the most billions among all the billionaires on the billionaire lists. Bill Gates, in second place, is worth a modest $94 billion, according to Forbes. Bezos first appeared on Forbes’ list in 1998, with a $1.6 billion fortune.

He made that much this week alone, on paper, as Amazon’s shares jumped in anticipation of “bigger than ever” sales on Prime Day, which ran from Monday to Tuesday. Amazon is now worth nearly $900 billion, and Bezos owns around 16% of the company’s shares. He became the world’s richest person earlier this year.

Although he is clearly doing pretty well for himself, a financial advisor might tell Bezos that he should consider diversifying his portfolio. It’s rarely wise to concentrate one’s wealth in a single asset, whether it’s a house or shares in a company you founded in a garage in the 1990s that now accounts for half of all e-commerce sales in the US.

So let’s say Bezos wanted to add some exposure to Europe. He’s familiar with Luxembourg—Amazon does a lot of business there. He could buy some stocks there. Or, actually, he could buy all the stocks in Luxembourg. Twice.

The Amazon founder’s vast wealth is enough to buy several countries’ stock markets outright. Currently, for example, he could purchase every company listed in Ireland, another popular place for tech firms, and still have a few billion dollars left over. Bezos may be better off, though, sticking with Amazon, which has gained more than 50% this year, adding around $50 billion—the total market cap of the Egyptian exchange—to the founder’s net worth.

Correction: A previous version of the chart suggested that the Taiwan stock exchange is worth around $100 billion—it is, in fact, much bigger than that (around $1 trillion, well beyond even Bezos’ reach). The market cap of the smaller Taipei Exchange is around $100 billion; the chart now shows a different market of that size—Dubai.