Originally published 2021-10-30.
In late October 2021 Senate Democrats unveiled a "Billionaires Income Tax" that would have taxed the richest Americans every year on the rising value of their stock, even if they never sold it. Elon Musk, then the world's richest person, attacked the idea on Twitter within hours. His main argument was that the tax would barely dent government spending, so ordinary taxpayers would end up paying anyway. He also said he would rather put his money toward getting humanity to Mars.
The plan never became law. But the fight over it is still one of the clearest examples of the debate about how, and how much, to tax extreme wealth. Here is what the proposal actually said, what Musk argued, and how well his numbers held up.
What the Billionaires Income Tax proposed
The bill was released on 27 October 2021 by Senator Ron Wyden of Oregon, who chaired the Senate Finance Committee. It was designed as a way to help pay for President Biden's Build Back Better spending package after Senator Kyrsten Sinema opposed raising ordinary income and corporate tax rates.
The key points were:
- Who it covered: people with at least $1 billion in assets, or with income of $100 million a year for three years in a row. Wyden's office said about 700 taxpayers would qualify.
- Tradable assets such as shares: taxed every year on their gain in market value ("mark to market"), at the long-term capital gains rate, which for the top bracket works out to 23.8% (a 20% rate plus a 3.8% investment income surtax). Losses could be carried back up to three years.
- Non-tradable assets such as real estate or private companies: taxed only when sold, but with an extra interest-style "deferral recapture" charge, capped so the total could not exceed 49%.
- Existing gains: a one-time tax on gains already built up, payable over five years.
This was a real shift. Under US rules, gains on assets are normally taxed only when they are sold. The very wealthy can hold appreciating shares for decades, borrow against them, and pass them on at death, often paying little income tax relative to their growing fortunes. A White House analysis in September 2021 estimated that the 400 wealthiest families paid an average federal income tax rate of 8.2% once unrealised gains were counted.
What it might have cost Musk and Bezos
Because most of his fortune was in Tesla and SpaceX shares, Musk was the obvious headline case. The Washington Post, as cited by IFLScience, estimated he could owe up to about $50 billion over the first five years, with Amazon founder Jeff Bezos owing about $44 billion. At the time Musk's net worth was put at almost $275 billion. These were press estimates rather than official ones, and the actual bill would have depended heavily on how Tesla's share price moved.
Musk's argument against the tax
Musk's first public reaction came in this post on 27 October 2021:
According to their own estimates, this tax only covers ~10% of the $3.5 trillion spending bill.
— Elon Musk (@elonmusk) October 27, 2021
Where will the other 90% come from?
The answer is you.
He followed up with a broader point about the national debt, which he put at roughly $28.9 trillion, or around $229,000 per taxpayer. Even taxing every billionaire at 100%, he argued, would only make a small dent, so the rest would have to come from the general public. His conclusion was blunt: Spending is the real problem.
In other posts he argued that the real question was who allocates capital better, governments or entrepreneurs, and warned that governments eventually run out of other people's money and turn to ordinary citizens. According to IFLScience, he also said he would prefer to use his wealth to take humanity to Mars
and to preserve human consciousness, a long-standing theme of his SpaceX ambitions.
Checking the numbers
Musk's core claim, that the billionaire tax alone could not pay for the whole package, was correct, and Democrats never said it would. It was one of several revenue sources. A few details deserve context:
- The "$3.5 trillion" figure was already out of date. Build Back Better began as a $3.5 trillion plan, but by late October negotiations had cut it to about $2 trillion, with Senator Joe Manchin pushing for less. The share any one tax would cover depends on which version you compare it with.
- Billionaire wealth is not the same as tax revenue. Musk was right that confiscating all billionaire wealth would not pay off the national debt. But the proposal was never about paying off the debt; it was about changing when gains are taxed.
- "The rest must come from you" was a prediction, not a feature of the plan. The other revenue proposals on the table, such as a corporate minimum tax, stronger IRS enforcement and a surcharge on incomes above $10 million, mostly targeted corporations and high earners rather than average households.
Why the plan stalled
The tax ran into trouble almost immediately. Senator Manchin reportedly dismissed it as overly complicated, and critics raised practical and legal objections: valuing assets every year, the risk that taxing unrealised gains could face a constitutional challenge, and the possibility that billionaires would be forced to sell shares to pay the bill. Supporters replied that the rules only applied to tradable assets with a clear market price, and that the alternative was letting the largest fortunes go largely untaxed.
When the House passed its version of Build Back Better on 19 November 2021, the billionaire tax was not in it; the bill relied instead on a surcharge on very high incomes and on corporate measures. Build Back Better itself then collapsed in the Senate in December 2021. Its slimmed-down successor, the Inflation Reduction Act, was signed in August 2022 without a wealth or unrealised-gains tax. Biden later proposed a different version, a minimum tax on the incomes of the very wealthiest households including unrealised gains, but it was not enacted either.
What happened next for Musk
A few days after the row, in November 2021, Musk asked his Twitter followers whether he should sell 10% of his Tesla stock, framing it as a response to the debate over unrealised gains. A majority voted yes, and he went on to sell billions of dollars' worth of shares over the following weeks. In December he said he expected to pay more than $11 billion in tax for 2021, which would have been among the largest individual tax bills in US history.
His critics argued that the very wealthy should still contribute more to public services like healthcare and education, and that one large tax bill after years of low effective rates did not settle the question. His supporters argued it showed the existing system already captured large sums when billionaires sold. Both points have stayed at the centre of the debate.
The bigger question the fight left behind
Stripped of the Twitter drama, the Musk-versus-Wyden clash was about timing. Should a fortune that grows on paper be taxed as it grows, or only when it is turned into cash? Countries handle this differently, and economists disagree about the trade-offs between fairness, administrative complexity and incentives to invest. If you want to judge future proposals, the useful questions are the ones this episode raised: who exactly is covered, how assets are valued, how much the measure would really raise, and what it is meant to pay for.
Sources: IFLScience, 29 October 2021: Elon Musk slams billionaire tax bill; Brownstein Hyatt Farber Schreck, October 2021: Wyden unveils Billionaires Income Tax; Yahoo Money: Democrats unveil billionaires tax on unrealized capital gains; Wikipedia, Build Back Better Act; Elon Musk on Twitter, 27 October 2021.
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