evidence: The latest-available data back up his statement, and it appears the gap is widening. [...] Sanders’ campaign told us his claim is based on a 2017 study from the left-leaning Institute for Policy Studies. It used Forbes’ list of the 400 richest Americans and data from a gold-standard federal government source on wealth. Those are 2016 figures, from the Federal Reserve Board’s Survey of Consumer Finances, which are updated every three years. [...] PolitiFact Wisconsin, "Bernie Sanders: Bill Gates, Jeff Bezos, Warren Buffett have more wealth than bottom half of U.S.," July 19, 2018