What is California’s Proposition 40? How the proposed 5% billionaire tax could work

California lawmakers are considering a proposed 5% wealth tax on billionaires in an effort to address income inequality and bolster funding for healthcare, food assistance, and education. The November ballot initiative, known as Proposition 40, has garnered significant support from both Democrats and Republicans alike, with polls indicating that a majority of voters favor the measure.

However, the initiative's passage remains uncertain, as some skeptics argue that it could drive wealthy individuals out of the state, resulting in a loss of future tax revenue and investment. Opposition to the proposal has been led by tech billionaires like Sergey Brin, who has invested over $100 million to defeat the measure and support counterarguments on the same ballot.

The tax would retroactively apply to January 1st, making it difficult for billionaires to escape the levy by relocating. While California has more billionaires than any other state, experts argue that the state's universities, research infrastructure, and talent make it unlikely that the tax will significantly impact tech startups or economic competitiveness.