Sergey Brin and 11 other billionaires and tech elite lined up against California's proposed billionaire tax

Google cofounder Sergey Brin and John Doerr have donated a combined $94 million to undercut California's proposed billionaire tax. Peter Thiel has donated $3 million to a separate group.Getty ImagesA handful of California's estimated 214 billionaires are trying to stop a proposed wealth tax.

Google cofounder Sergey Brin, who moved assets out of the state, has spent $82 million.Here are those joining him, including Peter Thiel, ex-Google CEO Eric Schmidt, and DoorDash CEO Tony Xu.California's tech billionaires and millionaires are going down spending.

This November, Californians will vote on whether to impose a billionaire tax after a last-minute push for Gov. Gavin Newsom to broker a deal failed to materialize.With their fortunes (or at least a lengthy court battle) potentially at stake, some of the biggest names in tech have poured in over $120 million to try to outright sink or complicate the chances of a one-time 5% wealth tax on state residents and trusts with assets over $1 billion.

In comparison, SEIU-UHW, a healthcare workers union, the wealth tax's primary backer, has received roughly $31 million thus far.Here's a look at some of the biggest names that are lined up against the taxSergey BrinSergey BrinGetty ImagesGoogle cofounder Sergey Brin was one of the biggest names to move assets outside California ahead of a key deadline in January.That hasn't stopped him from being the single largest funder of the opposition to the billionaire tax through a political committee called "Building a Better California."

All told, Brin has donated a staggering $82 million to Building a Better California so far. He cut his most recent check, a $16 million donation, on May 15, just over a month before the deadline for finalizing ballot initiatives.According to Bloomberg's estimates, Brin is worth $280 billion and is the world's third-richest person.

John DoerrJohn DoerrGetty ImagesKleiner Perkins chairman John Doerr famously wrote the firm's $12.5 million check for a stake in Goog