New Delhi, Oct. 4 -- Google co-founder Sergey Brin has spent $102 million so far to oppose California's proposed billionaire wealth tax. According to Fortune, campaign filings show that he is the biggest individual contributor opposing the proposal.

His donations went to Building a Better California, a political funding and advocacy group. It opposes the tax and supports business policies, affordable housing and infrastructure. Total funding against the proposal has crossed $187 million. Supporters have raised about $32 million.

Proposition 40 will appear on the ballot in November. It proposes a one-time 5% tax on California's 200 billionaires. Around 90% of the money would support the state's healthcare programme. The remaining 10% wou...