Generational wealth gap in the United States, 1989-2020. In 1998, the American population under 40 years old held 13.1 percent of America’s total wealth. In 2020, those under 40 hold only 6 percent of the total wealth. This means that millennials and Generation X own less than half of the wealth that older generations owned when they were the same age. Graphic: Self Financial, Inc.