If Sergey Brin’s $100 million donations this year hadn’t yet made it official, he has now: His political group is fighting the billionaire tax, and it has plenty of monied allies.
Building a Better California, the group the Google co-founder has propped up with $102 million to date this election cycle, disclosed almost $20 million from a handful of other Silicon Valley billionaires on Saturday, including venture capitalist John Doerr, cryptocurrency executive Chris Larsen and investor John Hering.
It also made its first $5 million donation to the committee formally fighting Proposition 40, the statewide Billionaire Tax Act put forth by Service Employees International Union-United Healthcare Workers West. The measure cleared the required threshold of 875,000 signatures and qualified for the November ballot in June, just weeks after the primary.
Brin’s 501(c)(4) group has already spent more than $50 million each on two competing measures, Props. 41 and 42.
The Saturday disclosures coincided with a fresh barrage of attacks on the measure by various Silicon Valley moguls and even businessman and TV personality Mark Cuban.
Over the weekend — and in response to arguments by Rep. Ro Khanna, one of the wealth tax’s most ardent congressional champions — Cuban described the measure as “the biggest ‘fuck you’ in the history of entrepreneurship.”
The measure would apply to people with $1 billion or more in assets with a one-time, 5 percent tax.
Brin’s committee reported receiving, from Aug. 4 to 10, $7.5 million from Doerr, $10 million from Ripple co-founder Larsen, almost $1 million from Hering and $250,000 from Neil Mehta, the Greenoaks Capital founder who bought several blocks of the Fillmore as part of a private, and controversial, revitalization project.
In turn, the group spent $15 million between Aug. 4 and 14 on the wealth tax’s official opposing committee, and the two other competing, anti-tax ballot measure committees that would sink the billionaire tax. All three committees received $5 million each.
“The state is at an inflection point,” said a spokesperson for Better California. “The impact of Prop 40 is clear: it will create a permanent hole in the state budget. The nonpartisan legislative analyst reports a likely ongoing decrease of billions in state income tax revenue, and Stanford University economists estimate Prop. 40 will end up costing the state nearly $25 billion. The result: there will be less money for schools, public safety, and healthcare — the problem Prop. 40 purports to fix.”
Proponents for the measure decried Saturday’s latest windfall.
“A few controversial billionaires like Sergey Brin would rather spend millions to fund shady opposition campaigns than simply pay their fair share in taxes so millions of their fellow Californians don’t lose their health care,” said Debru Carthan, the executive vice president of SEIU-UHW. “That’s shameful.”
Advocates argue the tax would help backfill about $100 billion in cuts to federal healthcare funding and affect roughly 200 billionaires. Aside from Khanna, the measure has received the backing of Vermont Sen. Bernie Sanders and the Teamsters California union. The California Democratic Party also endorsed the measure after a contentious vote earlier this month.
The California Legislative Analyst’s Office wrote that the tax would likely add “tens of billions of dollars” to the California budget, but could result in ongoing tax losses of “hundreds of millions of dollars or more per year” if billionaires flee the state, as Brin purportedly has already.
Gov. Gavin Newsom, who is widely speculated to be running for president in 2028, opposes it. Advocates previously made a compromise proposal of a 2 percent, two-year billionaire tax, but Newsom reportedly rejected it. California’s Democratic gubernatorial candidate, Xavier Becerra, opposes the measure as well.
Khanna has faced intense backlash from Silicon Valley over his stance — namely through a failed attempt to primary him with a tech-backed challenger, Ethan Agarwal.
Khanna didn’t respond to a request for comment.



A uniformly-applied “billionaire tax” (or something similar) at the federal level is the only way to go — as it won’t pit one state against another.
“United we stand; divided we fall” — remember that old adage?
Attempting to do this at the state level will inevitably fail as the billionaires will simply flee and/or avoid the state (as many have already done).
If California is dumb enough to pass this, it’ll be cutting off its nose to spite its face and shooting a massive hole in its financial foundation.
Focus on the smart approach: Take back Congress and the White House and actually deliver on long-promised federal tax reform that both massively simplifies the system and applies a progressive tax system without loopholes. (We have an historic once-in-a-lifetime change to do this in 2026 and 2028.)
And while you’re at it, get rid of gerrymandering, overturn Citizens United, establish term limits for the Supreme Court, and implement universal healthcare.
In sum: actually finally get good, long-promised stuff done for the middle and lower classes done!
Prop 40 text: https://oag.ca.gov/system/files/initiatives/pdfs/25-0024A1%20%28Billionaire%20Tax%20%29.pdf
Legislative Analyst Office report: https://lao.ca.gov/BallotAnalysis/Proposition?number=40&year=2026
What’s lost in all the noise (that this post is adding to), is that dubious little detail how the funds raised would go to administration, programs, investments and providers, but not patients, necessarily. (Hint, count how often we read “patient” in the prop 40 text). This looks like it’ll end up massive money grab, grifters falling over each other trying to get a piece of the pie. Here’s the core piece:
“Ninety percent shall be allocated to the Billionaire Tax Health Account for
health care funding, which may include expenditures to restore or address
any reductions in federal funding or state appropriations; investments to
protect or enhance Medi-Cal and other health coverage programs for low
and moderate-income individuals; support for safety net health care
providers serving vulnerable populations; preventing or mitigating facility
closures or reductions in service levels; and other investments to support
health care access, coverage, benefits, funding, services, and payments to
providers.”
Please br’er techlords, don’t move out of California!
San Francisco minus Tech equals Detroit
the detroit jokes are tired and disconnected from reality. the detroit area is and has been improving.
The people who remain after the Randian tech pirates leave for literally browner pastures will be just fine, better actually. With its bottomless need for farmland, dirty energy, water, debt, circular financing, and government handouts, hopefully “tech” goes the way of the dodo before it turns the US into a disintegrating autocratic police state dystopia. Oh, wait…
Tech literally props up the entire local economy. You have no idea how lucky you are to have folks with deep pockets subsidizing the rest of us. Take a trip to Detroit to see what happens to a city when its wealth creators desert it. You can buy a house there for one dollar, but you would not want to.
Anyone who believes that this would be a “one time only” tax is naive.
If it passes, it will be repeated.
And what’s so wrong with that?
Nothing if you want all the wealth /job creators and knowledge leaders to relocate elsewhere, leaving those who remain to pay higher taxes.
“wealth /job creators and knowledge leaders ”
IOW, “worship, serve, and subsidize us, or we’ll go Galt.”
Because you want a predictable tax system, not open season come every election year.
I hope all these people in the comments are being paid for their advocacy. (If they are indeed people.) Shilling for billionaires is pretty pathetic, but *unpaid* shilling for billionaires is beneath contempt.
For politicians who support this, you are setting yourselves up political suicide.
As for unions, do you really serve the needs of the many or just yourselves?
If you read and watch what is happening in Seattle, you should be concerned.
The Seattle natives are not happy. https://thepostmillennial.com/53-of-seattle-democrats-want-socialist-mayor-katie-wilson-to-resign-poll
Killing golden gooses is the wrong way to solve the problem, but better ways of regulating them is the solution. You just have to study, model, and systematize how places like Denmark, Finland, Norway, and Sweden do it. They regulate capitalism and their social services, not let them get out of control. If you kill the golden gooses, you destroy economic opportunities for yourselves. Better to have more businesses than more unemployed people and potentially more crime. You can only tax the remaining taxpayers (you, your friends, and families) so much until they want want you out.
Also, there is a difference between Social Democracy vs. Democratic Socialist.
One works and one does not when it comes the realities of their outcomes for the people.
Here’s an idea- the “billionaires leaving” California doesn’t matter. The concept that ALL these people are going to upend their business ventures rooted here is scaremongering- it is extremely disruptive to business in general, and impossible in many cases. Not all the money is tech. Is Wonderful going to move its farms? Are real estate moguls going to liquidate their property holdings? Will In-n-Out simply shutter?! OH THE HUMANITY! Moving will cost the vast majority of these people MORE money in ongoing yearly tax to California, as they will require income tax payments on any money “earned in California” which includes rental income. They know this very well and so they’re fighting this tax- most won’t go anywhere.
Now let’s say they do move, like Elon. (That worked out great for him, didn’t it?). Then what? What exactly? Investors WON’T invest in a startup because it’s in California and they’re not? They will simply close their businesses or move them to other states, where they need to train an entire new workforce? Or will they move hundreds of thousands of people out of state with lucrative relocation offers? Business is going to grind to a halt because every other business owner is going to upend their lives in panic that someday they MIGHT be a billionaire, and they MIGHT get taxed?
People live here, and entrepreneurship thrives here, because it is physically EASY. For the vast majority of people in this state, seasons don’t destroy your house every year, which is a HUGE mental relief. Your kids aren’t randomly stuck home for a snow day while you roll the dice on dying or not driving to work on ice. This translates to, for better or worse, a tech workforce with brains that puts in a lot of hours and focus, and a blue collar work force that isn’t spending every free hour working on their homes. This is a nice QUALITY OF LIFE, which is why people want to be here. The recent influx of tech avarice can disappear COMPLETELY and leave us back in the 2010 economy, which everyone will be fine with, except maybe the ones who paid $5M for their three bedroom house.
This isn’t an economic argument, or a state vs state issue- it’s a statement. THE PEOPLE are sick of THESE PEOPLE consistently refusing to contribute to society in any other way than reaping financial returns from every one else’s labor. NO ONE NEEDS A BILLION DOLLARS. NO ONE. The ONLY way these snakes are going to EVER pay their fair share of taxes is if WE MAKE THEM. Currently the system is tipped completely in their favor because THEY PAID FOR THE CHANGES TO TAX LAW. The only way we get change is if states like CA pass laws like this one via public ballot. Our representatives will never trade their campaign financing for the good of the country, which is INSANE, so it’s up to us. Otherwise the only thing the wealthy will continue to spend money on is making more money and evading tax, and things like, oh, I don’t know, fighting to make their mansion waterfront private so that the local community can’t visit the beach.
The union is acting in its own self-interest, but in the long run this approach will cost California billions in lost tax revenue. These companies and their employees should contribute their fair share through taxation; however, any significant tax policy changes should be implemented at the federal level. Otherwise, businesses will simply relocate to states with more favorable tax environments, resulting in job losses, reduced investment, and a shrinking tax base for California. Stupid policies are the reason CA is so unaffordable in the first place.
CA is so unaffordable because everyone wants to live here….
One overlooked aspect of this discussion is that Prop. 40 would allow the legislature to raise taxes on other CA residents with a legislative vote and agreement by the governor. It is effectively a way to end-run both Prop. 13 and the CA Constitutional requirement for a super majority to raise taxes. The sponsors know the money is with the broad CA population not the billionaires. Of course, the tax will trickle down, it is designed to do so.