SpaceX founder Elon Musk earned $13.9 billion from 2014 to 2018 and paid $455 million, which is 3.27 percent tax rate. In 2018, Musk paid no taxes at all.

Amazon CEO Jeff Bezos made $99 billion and paid $4.33 billion over the same four years - his tax rate was just 0.98 percent. And in 2007 he also did not pay income tax.

Warren Buffett evades payment the most. According to Forbes, his fortune grew by $24.3 billion between 2014 and 2018. During this time, Buffett paid $23.7 million (!) in taxes, less than ten cents for every $100 he earned.

When asked by journalists, Warren Buffett, Michael Bloomberg and Carl Icahn, who are involved in the investigation, replied that they paid as much taxes as they saw fit to pay.

https://www.propublica.org/article/the-secret-irs-files-trove-of-never-before-seen-records-reveal-how-the-wealthiest-avoid-income-tax

Biden administration started serious investigation, but not against richest criminals, but against journalists and their sources of information. As most of tax evasion in US happens due to private agreements between largest companies and richest people with IRS. As IRS close the eyes on obvious criminal schemes and offshore dealings.