California governor calls for national tax on super-wealthy and suggests the US should own a stake in AI companies US politics live – latest updates California’s governor, Gavin Newsom , called for a national “billionaires tax” on Friday as he fights a ballot measure targeting the ultra-wealthy in his home state. Newsom, who is expected to run for president in 2028, published his proposal the day after California officials certified a ballot measure to levy a one-time 5% tax on residents worth more than $1bn. The initiative, called the California Billionaire Tax Act, was brought by the Service Employees International Union-United Healthcare Workers West (SEIU-UHW) and would fund the state’s healthcare, education and food assistance programs.