Private income is either:
Many people with a private income of the second type are comfortably or well off and may not need a job for additional income. People in such a position can have other pursuits, e.g., as a philanthropist, or in the past as a gentleman scientist. Today among America's 146,000 highest income households, those making more than $1.6 million per year, 31% of all income was derived from investments.