The wealthiest Americans including Warren Buffett, Elon Musk and Jeff Bezos " paid little in federal income taxes at times in recent years despite soaring fortunes, according to Internal Revenue Service data obtained by ProPublica. The information published Tuesday shows how billionaires are able to legally reduce their tax burden, highlighting how the American tax system can hit ordinary wage earners harder than the richest people in the country. That's often because the richest Americans tend to have their wealth tied up in stocks and real estate, allowing them to avoid taxes on unrealized profits. The U.S. tax system focuses on income, not what is known as unrealized gains from unsold stocks, real estate or other assets. The records ... purport to show Buffett, head of Berkshire Hathaway, as having paid $23.7 million in federal income taxes on total income of $125 million from 2014 to 2018, which would indicate a personal income tax rate of 19 percent. ProPublica estimated that Buffett saw his wealth soar by $24.3 billion during that period and so his "true tax rate" was 0.10 percent. Musk, chief executive of Tesla, paid $455 million on $1.52 billion in income during the same period, when his wealth grew by $13.9 billion, accounting for a "true tax rate" of 3.27 percent. Bezos, chief executive of Amazon and the owner of The Washington Post, paid $973 million in taxes on $4.22 billion in income, as his wealth soared by $99 billion, resulting in a 0.98 percent "true tax rate."