It refers to how much of the world’s total wealth is held by citizens from that country. This has nothing to do with how wealthy the average citizen is, nor how much money the government has.
A few hundred Americans own more wealth than the citizens of any other single country.
The US government is able to incur so much debt essentially because its creditors know that it’s good for it. They’re confident that the government will not default on its debt or declare bankruptcy… nor collapse and cease to exist.
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