First, defining our terms:
Income is the money in your paycheck. It’s what you make from your job. Wealth, in contrast, is everything else. It includes stocks and bonds, home equity, other properties, investments, your retirement funds etc. Importantly, you can inherit wealth directly, but you cannot inherit income directly (most of the time).
The relationship between IQ and income is somewhat correlated; in general, people with higher IQs make more money:
But the relationship between IQ and wealth is all over the map:
From Zagorsky, Jay. 2007. Do you have to be smart to be rich? The impact of IQ on wealth, income and financial distress. Intelligence 35: 489-501.
Thanks to Conrad H.