California voters face a closely contested November 2026 ballot on this constitutional amendment, which would bar new state taxes on personal property ownership—including retirement accounts, financial assets, and business interests—while limiting retroactive taxes based on prior residency or activities. The measure's slight edge in trader pricing reflects its role as a competing initiative designed to nullify or override a separate billionaire wealth tax proposal if both pass with the higher vote total. Key drivers include substantial backing from high-net-worth donors, union opposition tied to revenue goals for healthcare and education programs, and broader debates over tax fairness versus fiscal impacts. Upcoming campaign spending, polling on wealth taxes, and any late endorsements or legal rulings on competing provisions could shift the balance before election day.