The closely contested odds around the California Retroactive Tax Prohibition Proposition reflect voter uncertainty over competing November 2026 ballot measures, including a union-backed billionaire wealth tax that would apply retroactively based on January 1, 2026 residency and net worth. This initiative would bar new state taxes on personal property such as retirement accounts, financial assets, and business interests while limiting retroactive tax liability tied to pre-enactment conduct or status. Recent qualification of both measures in June has intensified focus on their conflicting provisions, potential court challenges to retroactivity under due process standards, and fiscal impacts on revenue estimates. Upcoming campaign spending, polling on wealth taxation versus savings protections, and voter priorities on special taxes could shift implied probabilities in either direction before election day.