Union boss Dave Regan proposes a one-time 5% wealth tax on California's billionaires to replace federal healthcare funding cut by Trump's bill. Forbes estimates billionaire wealth grew from $700bn in 2019 to $2.1tn last year. Regan argues the 212% portfolio return means a 5% tax would barely register: "Their portfolio has returned 212 per cent... If their portfolio had returned 207 per cent, nobody would notice." The measure qualified for the November ballot, pitting 250 billionaires against 3.5mn people facing healthcare loss.

Silicon Valley billionaires have mobilized heavily. Sergey Brin poured $82mn of his $270bn fortune into Building a Better California, which raised over $100mn total. Other tech leaders including Chris Larsen, John Doerr, Michael Moritz, and founders of Stripe, Affirm, and DoorDash contributed seven-figure sums. At least $129mn has been collected from billionaires versus the union's $30mn. Brin, Larry Page, Peter Thiel, and Travis Kalanick reportedly moved residences before the retroactive January 1 deadline.

The fight splits Democrats. Governor Gavin Newsom opposes the state-only tax, warning it drives away "golden geese." French economists Thomas Piketty, Emmanuel Saez, and Gabriel Zucman support the tax, arguing billionaire flight is negligible. Betting markets give the tax less than one-in-three odds. The referendum tests whether populist anger can overcome concentrated billionaire power in America's most billionaire-dense state.