California’s 2026 Billionaire Tax Act would impose a one-time, 5% tax on the net worth of residents whose assets exceed $1 billion, targeting stocks, private businesses and intellectual property while excluding direct real estate holdings. Proponents estimate roughly $100 billion in revenue over five years to fund healthcare and counterbalance reduced federal Medicaid support.

Sergey Brin and fellow billionaires have contributed more than $100 million to the “Building a Better California” countermeasure, which seeks to prohibit new taxes on personal property and impose stricter audits on spending. Labor unions backing the tax have raised about $25.7 million, setting up a high-stakes ballot fight where the measure with the most votes prevails if conflicting initiatives pass.

Critics warn the wealth tax could prompt capital flight from California, potentially reducing local investment by tech firms. Alphabet may face indirect effects if key executives alter residence or investment strategies, while broader concerns center on maintaining a favorable climate for R&D and infrastructure spending in the state.