Proposition 42, a November 2026 California constitutional amendment, bars new state taxes on personal property such as retirement accounts and investments while restricting retroactive levies tied to pre-enactment residency or conduct. Its odds sit near even because it directly counters the retroactive wealth tax in paired Proposition 40, splitting voters between those prioritizing revenue for public programs and those opposing expanded taxation or constitutional changes. Business groups and anti-tax organizations have mobilized against the wealth tax's structure, while supporters highlight funding needs; legal debates over retroactivity and residency rules add uncertainty. Recent ballot qualification and campaign positioning have kept the measure competitive, with shifts likely from polling trends on tax initiatives, spending by opposing coalitions, or economic conditions influencing turnout among higher-income and independent voters ahead of the November election.