"The six wealthiest people in the world (have) as much wealth as the bottom half of the world's population, 3.7 billion people."
Bernie Sanders, Sept. 21 in a speech at Westminster College in Fulton, Mo.
Sanders' source is a 2017 Oxfam report that is put together using numbers from Forbes and Credit Suisse's Global Wealth Databook, according to Joshua Miller-Lewis, Sanders' press secretary.
The Oxfam report states that the eight richest men in the world had as much wealth as 3.6 billion people in the world, or half that population. But since that report, the numbers have changed: The rich have gotten richer while overall global wealth has decreased, according to the underlying data used by Oxfam.
Oxfam's calculations come from wealth estimates by Credit Suisse, a Swiss multinational financial services holding company, said Laura Rusu, policy and campaigns media manager for Oxfam America.
Based on the latest data from Credit Suisse, the wealth of the bottom 50 percent of the global population is $409 billion. The six wealthiest people in the world have about $416.2 billion combined, according to Forbes.
"The 1 percent now controls more wealth than the 99 percent of the rest of us combined, and it's only getting worse," Rusu said.
The six richest people, according to Forbes' billionaire list, are Bill Gates, Warren Buffett, Jeff Bezos, Amancio Ortega, Mark Zuckerberg and Carlos Slim Helú.
There are some notes of caution.
"I think this statement is correct, but it is not very meaningful because the bottom 50 percent has essentially no wealth," said economist Emmanuel Saez of the University of California at Berkeley.
While many of the economists we spoke to agreed that the statement is technically correct, the issue lies with wealth measures.
Most of the wealth of the rich is from fungible private wealth, which is an asset's interchangeability with assets of the same type. "It is probably the case that one-half the world's population has almost no fungible private wealth. So by that measure, Bernie Sanders may be right," said Richard Burkhauser, professor emeritus of policy analysis at Cornell University College of Human Ecology.
Rusu further explained that the Oxfam reports have seen a drop in private wealth, compared to the world's collective wealth, but this has to do with an improved data collection method and not necessarily a change in people's wealth.
"The dramatic drop isn't due purely to a sharp increase in inequality, but rather the availability of better data," Rusu told PolitiFact Missouri.
Sanders' statement is accurate but needs clarification. We rate this claim Mostly True.
Read more rulings at PolitiFact.com.