There are about 350 million people in the United States. A recent report claimed that the richest 1% of American controlled 42% of the nation’s wealth.

Answer 1

1 percent of 350 million = 3.5 million

that's somewhat misleading as it includes children under 18

also it doesn't reflect that the people in the top 1% may change entirely or substantially over time

bankrucpties or Jeffrey Epsteins can move some people from the top to the bottom over night

People in the 99% may move up into the 1% or close to it

A Gini index or Lorenz curve may be a better index of inequality, along with the Thiel and other measures of inequality.

control is an ambiguous word too. do they own the wealth or somehow control it like the CEO of a company?

it focuses on wealth not income

valuing an asset is not that easy, stocks can nosedive, valuing an asset depends on predictions of the unknown and unknowable speculative future.

Just a few problems with the claim