Silicon Valley’s richest outspent supporters more than 10 to one to kill California’s billionaire tax—and won | Fortune

California voters rejected Proposition 40, the billionaire tax measure, after opponents backed by Silicon Valley's wealthiest figures outspent supporters by more than a 10-to-1 margin. The coalition opposing the measure included Google co-founder Sergey Brin, and the defeat marks a significant win for the state's ultrawealthy in their first major electoral test against a targeted tax on extreme wealth. The lopsided spending gap underscores how concentrated financial resources can shape ballot outcomes in California, where direct democracy has long allowed well-funded campaigns to influence policy. The result is likely to discourage similar wealth-tax proposals in other states and could reshape how lawmakers approach revenue-raising measures aimed at high-net-worth residents. Attention now turns to whether proponents will revive the tax through the legislature or a future ballot initiative, and to how the outcome influences broader national debates over taxing the rich.