Proposition 42, a November 2026 California constitutional amendment, seeks to bar new state taxes on personal property ownership such as retirement accounts and investments while restricting retroactive levies tied to pre-enactment residency or conduct. Its near-even odds reflect direct competition with the proposed wealth tax in Proposition 40, which relies on a January 1, 2026, residency cutoff that opponents challenge as unconstitutional. Key balancing factors include ballot conflict rules favoring the measure with more votes, varying campaign funding from tax-reform groups versus revenue advocates, and broader voter debates over asset taxation versus fiscal needs ahead of the general election. Developments that could shift sentiment include updated polling on high-earner migration, endorsements from business organizations, or legal rulings on retroactivity that clarify the measure's scope.