They are a giant part of the US economy, however they don't represent 2/3 of US GDP, their sales are equivalent to that figure. These are global corporations th

They are a giant part of the US economy, however they don't represent 2/3 of US GDP, their sales are equivalent to that figure. These are global corporations that in many cases do business in nearly every country. Many of the largest S&P 500 companies have 2/3, 3/4 or more of their business overseas. They're typically under-represented in the US domestic economy, as the US is ~22% of global GDP, and these are typically among the largest corporations in their segments.