Some of the biggest names in business are speaking up about California's billionaire tax proposal. Others are physically relocating. The measure proposes a one-time 5% tax on California residents with assets exceeding $1 billion. The measure was certified for the November 2026 ballot on June 25 after receiving enough valid signatures. If the proposal passes, the tax would apply retroactively to all California residents as of January 1. Proposed by the Service Employees International Union-