Denoted in nominal USD. (They don't have to actually own that amount of USD, that's just the conversion rate.)
This market will only resolve to the exact name of a specific person. Non-specific or pseudonymous descriptions like "the first person to invent reliable fusion energy" or "Satoshi Nakamoto" will be ignored. Duplicate answers will be ignored.
If the person in question shares finances with family members, such as how Bernard Arnault's fortune is often listed under "Bernard Arnault and family", that still counts as one person. If a significant fraction of the fortune comes from more than one person, such as two $500 billionaires getting wealthy independently and then marrying each other, it only counts if they seem to truly share finances, such that either one of them has access to the full trillion if they wanted it.