California stands on the brink of a fiscal experiment unlike any other in modern U.S. tax policy. Voters will decide in November whether to impose a one-time 5% levy on the net worth of roughly 200 billionaires. Proponents promise $100 billion to fund health care, education and food assistance. Critics warn of an accelerated flight of talent and capital that could leave the state poorer. The numbers tell a story of extraordinary concentration. California billionaires control more than $2 trillion in wealth. That equals about half the state’s GDP. Their fortunes surged 144% between 2023 and 2025 alone, propelled by the artificial intelligence boom. Over four decades the real wealth of this tiny group multiplied 30 times while average real family income merely doubled. Short term gains. Long term divergence. A new study from the National Bureau of Economic Research lays out the case in stark terms.…