Tesla CEO Elon Musk. Win McNamee/Getty Images From March 2020 to April 2021, America's billionaires added $1.62 trillion to their wealth. A new report from IPS/ATF tracks how much billionaires have gained during the pandemic. These gains could signal that inequality keeps increasing during the pandemic. See more stories on Insider's business page. Over the last 13 months, American billionaires added $1.62 trillion to their wealth - a 55% increase.This was a finding in the latest report from the left-leaning Institute for Policy Studies (IPS) and Americans for Tax Fairness (ATF).