Proposition 42, a November 2026 California constitutional amendment, would bar new state taxes on personal property ownership such as retirement accounts, investments, and business interests while limiting certain retroactive levies tied to pre-enactment residency or conduct. Trader sentiment remains closely balanced because the measure directly counters Proposition 40’s proposed one-time wealth tax on billionaires, with both measures drawing substantial campaign funding and signatures collected by June 2026. Governor Gavin Newsom has signaled opposition to the wealth tax and support for competing initiatives that could neutralize it if they receive more votes. Key variables include voter turnout patterns on tax limitation questions, legal challenges over retroactivity and due process, and the scale of opposition spending ahead of election day. Any shift in polling on wealth taxation or clarification on ballot ranking rules could quickly alter implied probabilities.