Billionaire-Backed Groups Launch Ad Blitz Against California Wealth Tax

Organizations backed by mega-billionaires, including Google co-founder Sergey Brin and notorious venture capitalist Peter Thiel, have launched an advertising blitz aimed at convincing California voters to oppose a one-time, 5% wealth tax targeting the very richest people in the state. The two most prominent groups fighting the tax, which will appear on California's November ballot as Proposition…