Sergey Brin may be asked to pay $13 billion in estate taxes: Google co-founder spends $102 million to avoid paying it

Google co-founder Sergey Brin has spent $102 million so far to oppose California’s proposed billionaire wealth tax. According to Fortune, campaign records show he is the largest individual contributor opposing the proposal.

His donations went to Building a Better California, a funding and advocacy group. He opposes the tax and supports trade policy, affordable housing and infrastructure. Total funding against the proposal exceeded $187 million. Backers raised about $32 million.

Proposition 40 will appear on the ballot in November. He proposes a one-time 5% tax on 200 California billionaires. Roughly 90% of the money would support the state’s health program. The remaining 10% would fund education, food aid and administration.

Brin’s wealth is nearly $260 billion. So he could face a tax bill of about $13 billion.

The debate reflects California’s stark divide between rich and poor residents. Its economy is worth $4 trillion, roughly equivalent to that of the United Kingdom. Nevertheless, 18% of its inhabitants live below the poverty line. This is the highest proportion in the country, partly because the cost of living is high.

Former Google chief Eric Schmidt and PayPal co-founder Peter Thiel have also funded opposition groups. Brin linked his concerns to his family’s escape from the Soviet Union in 1979. He said he feared California might face similar conditions.

Governor Gavin Newsom is also against the measure. They argue that losing wealthy taxpayers could reduce the money available for public services. These include education, childcare, policing and firefighting.

Meanwhile, some billionaires have moved their business interests outside of California. State records now list Brin as a Nevada resident. In March, he reportedly bought a $51 million home near Miami Beach.

Google co-founder Larry Page moved several assets out of state. His family office, Koop, was incorporated in Delaware in December 2025. Oceankind, founded by his wife, Lucy Southworth, was incorporated around the same time.

Financial impact on billionaires

However, the financial impact of billionaire departures remains unclear. The six billionaires expected to drop out could have contributed roughly $27 billion, according to the proposal. The measure is expected to raise $100 billion over five years.

A May research paper offered a different view. California billionaires paid $4.1 billion in income taxes last year, according to Fortune. That represented about 0.2% of their combined $2 trillion fortune.

Even universal retirements would take about 25 years to offset projected tax collections. If one-quarter remains, the income tax loss would equal a century, Fortune added.

Scholars described the proposed tax as small compared to the billionaires’ profits. They described it as large compared to their existing tax payments. The debate continues until November.