The researchers found that a significant amount of U.S. currency is held abroad, but not as much as previously thought. They estimate that between 30-37% of U.S. currency is overseas, not 65% as commonly believed. This information was based on official data from the Federal Reserve. The study also revealed that the U.S. government has earned $287 billion from overseas currency holdings. Additionally, the researchers estimated that the unreported economy in the U.S. is between$1.9 - $2.4 trillion, leading to a tax gap of$400- $550 billion.