Google cofounder Sergey Brin is one of the many California-based billionaires pouring millions into donations ahead of the state's proposed wealth tax. Brin, along with other tech executives, venture capitalists, and philanthropists, donated a combined $35 million to ballot measure committees in January, supporting affordable housing ballots in California, per a disclosure seen by Business Insider. The disclosure was filed by the coalition "Building a Better California." Brin was the largest contributor in the filing, donating $20 million. Others donated large sums on various days in January, like former Google CEO Eric Schmidt and PayPal CEO Max Levchin, who donated $2 million and $1 million, respectively.