The California arm of the Communist Party USA has officially endorsed Proposition 40, a one-time 5% tax on the state's wealthiest residents, urging voters to approve the measure. The group stated on its website that "it’s up to all of us, the 99%, to turn out with a massive vote and show these billionaires that it’s time for them to pay their fair share."

The endorsement places the Communist Party alongside organized labor in supporting the proposition, while it faces opposition from some of Silicon Valley's richest individuals and prominent Democratic figures, including Gov. Gavin Newsom and gubernatorial candidate Xavier Becerra.

Proposition 40, sponsored by SEIU-United Healthcare Workers West, aims to generate approximately $100 billion through a wealth tax. The measure earmarks 90% of the revenue for healthcare services and the remainder for food assistance and K-12 education. The Communist Party argued that the funds are necessary to address shortfalls created by federal policies, which they attributed to President Trump, and to prevent the shutdown of essential services that would disproportionately affect working-class Californians.

Governor Newsom has publicly opposed Proposition 40, expressing concern that the tax could prompt wealthy individuals and companies to relocate, potentially leading to a loss of income tax revenue for the state. Supporters of the measure, such as Dave Regan, head of SEIU-UHW, contest this claim, stating there is "absolutely no evidence that billionaires leave" the state, asserting that the wealthiest individuals have the flexibility to reside anywhere globally.

Wealthy Californians, including Google co-founder Sergey Brin, who emigrated from the Soviet Union with his family as a child due to communism and antisemitism, have reportedly invested tens of millions of dollars to campaign against Proposition 40. They have also backed rival propositions, 41 and 42, which could undermine Proposition 40 if they receive more votes. The Communist Party specifically called out Brin and his allies in their endorsement, urging voters to reject propositions 41 and 42 while approving the wealth tax, stating, "these midterms are not for sale."