Proposition 42 would amend the California Constitution to bar new state taxes on personal property ownership, including retirement accounts and investments, and restrict certain retroactive levies tied to pre-enactment residency or activities after January 1, 2026. The measure directly counters the competing Proposition 40 wealth tax initiative, which targets billionaires' net worth based on that same residency cutoff, with the higher-vote measure prevailing in conflicts. Trader sentiment remains near even because business and reform groups back the tax limits while proponents of expanded revenue for services oppose them, amid ongoing qualification battles, signature costs, and legal questions over retroactivity. Upcoming campaign spending, endorsements from chambers of commerce or labor organizations, and any shifts in polling on the paired measures could alter the balance before the November 3 ballot.