Most Of Billionaires’ $7.6 Trillion Has Never Been Taxed

We really, really need a Billionaires Income Tax.

Total Billionaire Wealth Is Up 160% Since First Trump Tax Law; Proposed New Levy Would Finally Tax Unrealized Gains of the Wealthiest

American billionaires reached a record breaking $7.6 trillion of personal wealth as of Labor Day 2025, up $4.7 trillion (or 160%) in the less than eight years since the first Trump-GOP tax law was enacted in December 2017, according to the latest billionaires report from Americans for Tax Fairness (ATF) based on Forbes data. Most of that wealth increase (an estimated 56%, or $4.2 trillion) has never been taxed and may never be under current law. But key Democrats, Senator Ron Wyden (D-OR), Rep. Steve Cohen (D-TN), and Rep. Donald Beyer (D-VA) are introducing a major overhaul in the tax code which would finally end that injustice by taxing billionaire wealth gains as they are made.

The number of billionaires tracked by Forbes is up by nearly 40% since the end of 2017, growing from 551 to 905. But the top 15 of these billionaires–who are each worth over $100 billion– have seen their wealth grow by more than 300% and now collectively make up over 30% of the wealth of all the U.S. billionaires listed by Forbes. These oligarchs at the top of the economic food chain include Elon Musk, who has seen his wealth grow 20-fold, and AI tycoon Jensen Huang, whose wealth has increased by 30 times over the last eight years.

Forbes compiles the longest-established and best-respected list of billionaires, most of whom are prominent business personalities. But government research indicates there are many more “quiet” members of the billionaire class: an ATF extrapolation from the most recent comprehensive survey indicates there may be as many as 4,400 American billionaires with a combined net worth of almost $13 trillion. That figure includes an estimated $7.6 trillion in eight-year wealth growth that may never be taxed under current rules.

Source: Americans for Tax Fairness

Enactment of the 2017 tax law is used as the starting point to track billionaire wealth growth because it likely turbo-charged the process. The law’s centerpiece was a two-fifths cut in the corporate tax rate, reducing it from 35% to 21%. Since 93% of corporate stock is owned by the wealthiest 10%–including billionaires–corporate tax cuts are by definition tax cuts for the rich. The law also reduced the top individual tax rate, the one that applies to the great bulk of the richest Americans’ income. Meanwhile, the law failed to close any of the many loopholes enjoyed by the rich; the biggest one for billionaires is the tax-free status of wealth-growth income.

Leading economists have determined that on average, the wealthiest 400 families paid an effective federal income tax rate of just 8.2% in recent years, when the increased value of their stock is counted. That means billionaires can pay lower tax rates than middle-class workers like teachers, nurses, and firefighters. An analysis of billionaire tax data found that 26 of the wealthiest billionaires paid an effective tax rate of just 4.8% on a $500 billion increase in their collective fortune between 2013-18. ProPublica also found that billionaire Jeff Bezos paid $0 in federal income tax from 2007 through 2011.

Sen. Wyden’s proposed Billionaires Income Tax (BIT) would tax the wealth gains of billionaires and those with consistent income above $100 million. Currently, such investment gains are only taxed if the underlying asset is sold. But the ultrawealthy don’t have to sell to benefit. They can secure low-interest loans secured against their rising fortunes and live luxuriously tax-free. Under Wyden’s plan, such wealth-growth income would be taxed every year just like worker wages are now. The Joint Committee on Taxation estimated this proposal would raise $557 billion in new revenue over the next decade from just a small number of ultra-wealthy oligarchs.

METHODOLOGY: The estimated number of billionaires is based on the Federal Reserve Board’s triennial Survey of Consumer Finances (SCF). The most recent report, based on survey data from 2022, found 1,665 billionaires, not including the Forbes 400 which the SCF purposely leaves out (pg 47). It is possible to extrapolate–based on stock market growth and the number of super-rich households with close to but less than a billion dollars in the last survey–how many new billionaires may have been minted in the subsequent three years. The hyperwealthy are heavily invested in the stock market and the benchmark S&P stock index has grown by 60% since September 2022.

That rise in the stock market has thus likely lifted 4,000 households worth at least $630 million in 2022 into the ranks of the billionaires today. It’s possible, of course, that the average increase in billionaire wealth has lagged the market: if the average wealth growth among multi-centimillionaires was 50% instead of 60%, that would lead to a little under 3,500 billionaires; if 40%, then a little over 2,700. The complete estimated total is achieved in each case by adding the top 400 excluded households.