Silicon Valley is mounting a significant financial defense against California’s Proposition 40. This ballot measure proposes a one-time 5% wealth tax on residents worth over $1 billion. Proponents state the funds would raise $100 billion over five years for health care and education, yet major tech figures view the move as a threat to the state’s startup ecosystem.

Campaign finance records indicate that prominent figures are directing millions toward opposition committees. Peter Thiel, Chris Larsen, Sergey Brin, and John Doerr are among those bankrolling efforts to defeat the measure. Several of these donors have already reduced their physical or financial presence in California, citing the legislative environment.

The debate reflects a divide over tax policy and economic incentives. Supporters of the tax, including Rep. Ro Khanna, suggest it is a fair contribution from those who built fortunes within the state. They propose deferral options for founders who are illiquid but wealthy on paper, ensuring the state collects funds when assets are eventually sold or dividends are paid.

Critics like Mark Cuban argue such taxes cause founders to relocate. They contend the policy ignores the reality of illiquid assets and risks driving away the talent necessary for innovation. As the November election approaches, the battle between those prioritizing public funding and those warning of capital flight remains a central point of contention for California's economic future.