Sergey Brin's $102 million against Prop 40 equals 0.8% of the tax he could owe

A nine-figure campaign is cheap for a man facing a $13 billion bill. Brin's $102 million is about 0.8% of what a 5% levy would take from his net worth of nearly $260 billion, and about 0.04% of the fortune itself ^[1][5][1][2]. On its own it is more than three times everything the measure's supporters have raised ^[4]. It is also about 55% of the opposition's total, a campaign Eric Schmidt and Peter Thiel have funded as well ^[5][7].

Brin has made the fight personal. "I fled socialism with my family in 1979 and know the devastating, oppressive society it created in the Soviet Union. I don't want California to end up in the same place," he told the New York Times in a statement in April ^[6]. The Nevada address makes the donation harder to price. So does the $51 million home near Miami Beach he reportedly bought in March ^[8][9]. If the move takes him outside the tax, the $102 million is buying something other than his own exemption; Building a Better California also backs pro-business policies and housing and infrastructure affordability, according to Fortune ^[10]. If the move does not count, the donation is a hedge. Fortune's account does not say how the measure defines a resident or when residency is tested.

Larry Page has moved entities. Koop, his family office, was incorporated in Delaware in December 2025, and Oceankind, the ocean science nonprofit his wife Lucy Southworth founded in 2018, was incorporated there around the same time ^[11]. The tax reaches about 200 people ^[4]. For the firms that advise them, planning at the top of that list was under way by December 2025 ^[11].

The state's $100 billion five-year estimate is 5% of the roughly $2 trillion California's billionaires hold ^[12][13][6]. Each departure, or rather each departure that escapes the tax, comes off that figure. If the six expected leavers are outside it, the take falls to about $73 billion ^[14][8]. Brin accounts for about 48% of the six's share ^[7].

The NBER paper argues departures matter less than they look. Even if every billionaire left, Fortune reports, it would take about 25 years of lost income tax to cancel out the $100 billion, and a century if a quarter left ^[13][17]. That comparison assumes the leavers still pay the levy. Gov. Gavin Newsom opposes a measure that would fund his own state's health care program, arguing it would erode the tax base ^[16]. "The fact is it actually will reduce investments in education," Newsom said in a Bloomberg Businessweek interview ^[15].

The vote can go three ways: it fails, and Brin's campaign cost him 0.8% of a bill he never pays; it passes with the base intact, and the state collects close to $100 billion over five years; or it passes after the departures and collects nearer $73 billion ^[1][12][8]. I think a yes vote most likely ends up in the third case, because Brin and Page have already changed an address or a domicile ^[8][11]. The counter-thesis is the NBER view that billionaires paid so little California income tax that their leaving barely dents state revenue ^[13]. For the levy itself, that view holds only if the residency test reaches people who have already moved.