Brin’s money bought the prohibition, not the defenceSergey Brin · Google co-founder · Building a Better California
- What they did
- Founded Building a Better California in January 2026 with $20M and funded it to $102M by August. Through 20 October the committee deployed more than $304M: about $118.5M against Proposition 40 and about $186M for Propositions 41 and 42. He relocated to Nevada in December 2025, before the 1 January 2026 residency date that fixes liability under Prop 40.
- Dated to this window
- California voted 3 November. As of 4 November: Prop 40 (one-time 5% levy on net worth above $1bn) losing roughly 55.6–44.4 with 54–60% counted; Prop 42 (constitutional bar on taxing financial assets, private businesses and pensions, and on retroactive taxes) leading at about 54–55%; Prop 41 rejected at about 52% no. Under California’s conflicting-measures rule, the countermeasure that outpolls Prop 40 nullifies it.
Consensus read
Billionaires spent roughly $300M to kill a tax on billionaires, outspending the sponsoring union by more than 9 to 1, and it worked. Self-interest, plainly and expensively expressed, with the richest donor having the most to lose.
Contrarian read
The largest donor had arguably the least direct exposure to the measure he spent most against, and the money was not mainly spent on that measure. Roughly 61% of the committee’s deployment went to Props 41 and 42 — not a defence against this levy but a permanent constitutional bar on the whole category.
The allocation is consistent with buying a prohibition and a standing state political vehicle. Defeating Prop 40 was the cheaper, disposable half.
Evidence that discriminates
- The split: $118.5M against Prop 40, $186M for Props 41 and 42. If the object were simply to defeat Prop 40, the marginal dollar belongs in the Prop 40 “no” campaign. Evidence consistent with both readings would be one large undifferentiated anti-40 campaign. This is not that — it is a 39/61 split against the thing everyone says the money was for.
- The move predates the measure. December 2025 is before the 1 January 2026 cutoff, before the committee launched, and before the measure qualified. You cannot describe a December 2025 relocation as a response to a campaign that began in 2026.
- The instruments differ in duration. Prop 40 is one-time and keyed to a fixed past date. Props 41 and 42 are permanent and prospective. Only the second category is worth $186M to someone who has already stepped outside the base.
- The result split matches the design. Voters rejected Prop 41 and passed Prop 42. The durable instrument carried; the one that merely audited future taxes did not. The money bought the thing that outlives the election.
The number under the vote — attacking the measurement
The most-cited figure in the campaign was Jaros & Rauh (NBER working paper w35899, Hoover Institution, October 2026): a $30bn one-time take against $38.9bn of lost future income tax, net −$39bn, with the state worse off in 85% of 100,000 simulations. Two problems sit in the denominator, not the conclusion.
- The departure adjustment is not a choice variable after 1 January 2026. The study discounts the base by roughly 30% for departures estimated from Forbes rankings, real-estate reports and public relocation announcements gathered through about October 2026. But liability attaches to residency on one day at the start of that window. An announcement made in August cannot shrink a base fixed in January. The estimate uses a year-long announcement window to reduce a one-day measurement.
- The horizons do not match. The levy is modelled as one-time; the migration loss is modelled as permanent. Boll, Saez and Zucman make the point directly and estimate that even if every billionaire left permanently it would take roughly 25 years of foregone income tax to equal the $100bn proponents claimed.
- Third-party check on the central input. California’s own Legislative Analyst’s Office puts the annual income-tax loss at under $1bn, against the study’s $1–3.5bn. That is a spread of up to 3.5× on the number the whole net-loss figure rests on.
Neither side here is disinterested — SEIU-UHW sponsors the measure and Saez advised on its design unpaid. The mismatch between a one-day measurement date and a year-long announcement window stands independently of who points it out.
What would falsify me
Campaign filings showing that Brin’s own $102M was earmarked predominantly to the Prop 40 opposition rather than to Props 41 and 42. The 39/61 split is the committee’s total deployment, not a trace of his specific dollars — that is the weakest joint in the argument and I am naming it.
Also: a Franchise Tax Board determination treating him as a 1 January 2026 California resident would make him liable and restore the ordinary self-interest reading entirely. Residency is a facts-and-circumstances test; announcing a move does not settle it, and economists who helped design the measure argue he likely remained a resident.
On the study: if the text of w35899 measures departures as of 1 January 2026 rather than through October, the denominator criticism fails and I withdraw it. I have not read the paper itself, only reporting of it.
Pattern vs his own historyReported as his first large-scale political vehicle — a committee founded from scratch in January 2026 and funded to nine figures within eight months, against negligible prior political giving. Treat “negligible prior giving” as press characterisation rather than a filing I verified.