In November, Californians will be asked to approve Proposition 40, the nation’s first ballot measure that would impose a one-time 5 % tax on the net worth of every resident whose assets exceed $1 billion. The revenue, projected at roughly $100 billion, is earmarked mainly for shoring up a public health system that lost federal support under the previous administration. With an estimated 200 billionaires in the Golden State, the proposal could become the most consequential fiscal experiment in U.S. history.
The drive behind the initiative traces back to a “wealth tax movement” that has gathered steam across the country. Earlier this year, a dozen states introduced millionaire or billionaire taxes, while Maine, Washington, Hawaii and Rhode Island already passed similar levies. At the federal level, Senator Bernie Sanders and Representative Ro Khanna have introduced a national version, echoing the momentum that has not been seen since the Progressive Era.
Heavy money, high stakes
Opponents of Proposition 40 have assembled what may become the most expensive ballot battle in California’s history. More than $300 million has been poured into the “no” campaign, with Google co-founder Sergey Brin alone contributing over $205 million. A coalition that includes Governor Gavin Newsom the California Teachers Association and the United Domestic Workers union argues that a billionaire tax would prompt the ultra-rich to flee the state, shrinking the tax base and worsening fiscal gaps.
Supporters, by contrast, are operating on a shoestring budget. Their total spending barely exceeds $200 000, relying heavily on the national profile of Senator Sanders and grassroots canvassing to spread the message. Professor Brian Galle of UC Berkeley, a co-author of the measure, warned that without the estimated $100 billion, households could face an extra $7 500 in out-of-pocket health costs over the next few years.
Economic backdrop fueling the debate
Forbes recently recorded a historic 3 428 billionaires whose collective wealth totals $20.1 trillion—$4 trillion more than a year ago. Elon Musk topped the list with a net worth of $839 billion, becoming history’s first trillionaire earlier this summer. Meanwhile, the 25 wealthiest Americans pay a “true tax rate” of only 3.4 %, a fraction of what nurses and teachers contribute, even though they control roughly 2 % of national wealth—an amount comparable to the entire bottom half of the country.
Labor’s share of economic output has slipped to 52.8 %, the lowest level recorded since systematic data began in 1947. Corporate margins have roughly tripled since 1980, and after-tax profits now sit above 12 % of GDP, nearing historic peaks. Economist Thomas Philippon estimates that weakened competition costs the average household about $300 each month, underscoring the link between corporate concentration and household strain.
Critics say a tax alone won’t curb inequality
While many champion the wealth tax as a direct way to redistribute billionaire fortunes, some analysts argue the measure targets a symptom rather than the root cause. Documentary filmmaker Alex Gibney notes that Tesla and SpaceX CEO Elon Musk spent nearly $300 million influencing a presidential election and then championed cuts to federal agencies that once investigated his firms. Yet the concentration of power resides in the corporate structure itself.
Since the 1970s, the doctrine of shareholder primacy—advocated by economist Milton Friedman—has reshaped American firms to prioritize profit above all else. Stock-based compensation and share buybacks now channel over a trillion dollars annually to shareholders, diverting funds that could otherwise support wages or productive investment. Corporate lobbying, bolstered by a 1971 memorandum from future Supreme Court Justice Lewis Powell now outspends labor and public-interest groups 34-to-1, and the 2010 Citizens United decision has removed meaningful caps on corporate political spending.
Critics therefore propose a two-pronged approach: retain the wealth tax to fund immediate needs, but also pursue reforms that dilute corporate power—reviving antitrust enforcement, expanding labor-law protections, and encouraging alternative ownership models such as purpose trusts, employee-owned firms and benefit corporations. As economist Emmanuel Saez notes, if a permanent version of Proposition 40 were adopted, it could inspire similar initiatives nationwide, potentially reshaping the balance between capital and community.
