entrepreneur, investor, contrarian
Miami, FL
Joined February 2009
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Formula for startup success: Find large highly fragmented industry w low NPS; vertically integrate a solution to simplify value product.
Keith Rabois retweeted
There are only 130 US tech companies, public or private, valued at $10B or more (decacorns). That’s roughly 20 to 30 new companies per decade, for the last five decades. This year alone, with a quarter to go, there have been 42 decacorns minted privately. Either this is the most economically transformative event since the industrial revolution, or we’re getting a wee bit ahead of ourselves.
LOL.
this California wealth tax thing is just incredible.
so in October 2025, a California healthcare union proposed a "one time" 5% tax on any billionaire's wealth. the ballot measure will be voted on next month. In early December 2025, California announced that it would be a retroactive tax if passed, applying to anyone with CA residency as of Jan 1, 2026. The objective is to pay for Medi-Cal, California's incredibly dysfunctional healthcare system. (which also functions as a glorified welfare apparatus, but that's a discussion for another time).
polls reveal that the CA electorate is split around 50/50 on the tax, but prediction markets only give Prop 40 a ~23% chance of passing (there are competing measures on the ballet that would nullify it).
there are 200 billionaires in CA, worth collectively somewhere between $2.3 and $2.6 trillion. 5% of that is around $100b, accounting for a small amount of attrition. proponents of the tax forecasted a significant windfall, assuming only a 10% departure rate.
supporters thought they were being clever with the retroactive concept. no billionares would leave CA in the few short months between the tax being proposed and the residency cutoff date, without the tax even having passed yet, right?
well as it turns out, they did.
a new paper [1] from two academics at Stanford called "The Net Present Value of the California Billionaire Tax Act", argues that not only did more billionaires leave due to the proposed tax than its proponents expected, but that the value of the tax, if it does pass, is actually negative.
proponents of the tax only assumed 10% avoidance, that is, only 10% of the taxable base of targeted billionaires would leave CA within the very short Oct-Dec 2025 window. Jaros and Rauh, the Stanford academics, find that a lower bound of 28.6% of the taxable base managed to leave.
just based on known departures, those departures total $577b in net worth, or $28.8b in potential tax lost. this of course does not capture everyone (many left without announcing their departure), so the authors normalize to departure rates estimated from other wealth tax events, and apply other discounts for litigation, arriving arrive at a figure of only $28-$36b in forecasted tax revenues.
but this isn't all! all of the income taxes paid by the departed billionaires are also forsaken. the authors estimate that CA billionaires pay $3.3- 5.8b in annual income taxes. they assume a midpoint of $2b lost in annual collections from departed billionaires. the net present value of that lost income stream is -$68.9 billion.
so when you add it all up you get:
+ $30b one-time tax windfall (estimated)
- $69b in present value of lost future income taxes
= - 38.9b overall net present value of the tax
of course, this analysis is highly estimate driven. the authors simulate the parameters 100k times and find a negative NPV of the implemented tax 85 percent of the time.
and if the tax doesn't pass, which it's not looking like it will, California still ended up losing at least $577b in departed net worth, and they have permanently poisoned the well with entrepreneurs who will now worry about future wealth taxes.
[1]: nber.org/system/files/workin…
Keith Rabois retweeted
#1 way to impress VCs IMHO:
Be incredibly deep and strong on the competition. Super deep. Know literally everything.
And be extremely honest and even complimentary about their strengths, and your gaps.
The best founders always do this.
Keith Rabois retweeted
It’s been amazing to work with Khosla Ventures. The entire team is incredibly smart and hard-working. And of course @vkhosla is a legend.
thrilled to co-lead this round with @vkhosla @SStrohband @khoslaventures . @bobmcgrewai is a singular leader, and we in the US could not be more fortunate he’s applying his energy to improving American manufacturing. congratulations!
Keith Rabois retweeted
We started Arda in 2025 to speed up American manufacturing. We have spent the last year building with Anduril as our design partner. Today we are launching the company publicly on CNBC and announcing our Series A: $160M at a $1.5B valuation.
Our platform helps manufacturers design and operate manual assembly lines, putting designs into production faster now. Next we'll build automated lines that can be reconfigured as quickly as human workers, letting America make products that now require armies of workers in Asia.
Keith Rabois retweeted
A few years ago, Effective Altruists decided to place "moral weights" on human lives.
They say that humans are worth about two pigs or three chickens.
These are the kind of models that will guide the distribution of funds through Anthropic's "public good" operation.
Keith Rabois retweeted
@alexrkonrad was kind enough to write about our funding, how we show up for the people we serve, and our vision for Tolan: upstartsmedia.com/p/tolan-ra…
Keith Rabois retweeted
Last year we launched Tolan, inspired by a vision of AI that sees you and believes in you, not one that books restaurant reservations for you.
Your Tolan shows up for you at 3am when you’re alone with your newborn. On your commute when you’re anxious about the day ahead. When you just finished a new show and none of your friends have watched it yet.
The people who love Tolan are parents. Caregivers. Moms in Dallas and Dads in Atlanta. People who aren’t trying to optimize and be more productive, but who simply want to feel seen and supported in their aspirations.
This month more than 250k people will spend time with their Tolan. Those users have exchanged billions of messages across more than 70m conversations over the last year.
Today, we're announcing $30m in additional capital from @mignano and @usv, with @khoslaventures and @rabois doubling down, bringing our total capital raised to $60m.
To celebrate, we made a short film celebrating some of the ways that Tolans show up :)
Keith Rabois retweeted
Macron blames France’s economic problems on the Iran war. But after nearly a decade in power:
Government debt soared from 97% to 116% of GDP.
Budget deficit doubled from 2.6% to 5.1%
Growth has been anemic throughout his nine years, slowing to 0.8% in 2025.
Poverty increased by 1.25 million people.
All before the Iran war. Macron can’t escape his own record.
Keith Rabois retweeted
Premise:
Incentives drive all human behavior.
The corollary:
How to destroy a country:
A vast social security and support system that serves as a magnet for those who would rather not work.
An open immigration policy that does not screen immigrants to determine their ability and willingness to provide for themselves and their families.
An open immigration policy that does not screen for political and/or religious ideologies that are a threat to the country.
Economic incentives large enough to incentivize immigrants on the state dole to have large numbers of children, but insufficient for educated and economically productive mothers to be able to quit to raise a family.
The declining fertility of the most educated and productive women due to their delay to begin a family as a result of their desire and/or need to advance their careers, among other reasons, to live a life they deem consistent with their educational achievements and/or to repay their student debts.
Amnesty programs that give citizenship and voting power to illegal immigrants without consideration of their economic productivity or their threat to the country due to their religious or political ideologies.
The changing demographics and increased population due to the above factors.
The state responding to protests by increasing social support.
The continued failure to punish and hold accountable violent and looting rioters.
Government managed by a massive and growing unelected bureaucracy.
Government fraud, waste, and abuse contributed to ballooning budgets.
Anti-business legislation that makes it difficult for businesses to compete in a global marketplace being disrupted by AI, including restrictions on firing even poorly performing employees.
Overly burdensome, globally uncompetitive, corporate taxation.
Continuous increases in personal taxes to raise funds to provide for the rapidly growing welfare state.
The substantial majority of the tax burden levied on a small percentage of the population.
A growing percentage of the electorate paying no taxes and receiving welfare.
The introduction or threat of a wealth tax including the taxation of unrealized gains, i.e., taxes on paper wealth.
The flight of the most productive business builders and highest taxpayers to lower tax countries with lesser security concerns.
A growing percentage of the electorate voting for candidates that support increased welfare and laws favorable to, and/or that match the cultural and ideological needs and desires of a growing unproductive immigrant population.
The rapid rise in anti-semitism and inadequate efforts to address this hatred.
Increased borrowing by the state to fund the growing social burden.
Higher sovereign interest rates due to all of the above.
The resulting need to reduce expenditures to make the math work.
Increasingly violent protests that make life less livable for the productive and law abiding citizens leading to their accelerated departure.
And so on…
Keith Rabois retweeted
What’s happening in Paris and Milan is no surprise to anyone who has spent time around young people in Europe during the 2010s:
Virtually all of them were working on their 4th masters degree in social welfare, were unmarried, attended communist dinners every night, and regularly participated in riots.
Now the economy is suddenly transforming and they have nothing to show for it.
Spellbook is saving a Fortune 100 company $21 m in outside counsel legal fees with autonomous contracting. Want to save wasted $$$ on legal costs instead of buying software? spellbook.com/reduce-outside…
Keith Rabois retweeted
Thrive Capital’s Dr. Nworah Ayogu tested OpenAI’s reasoning models on New England Journal of Medicine’s “House M.D.-level” case studies:
“OpenAI & o1 was batting 10 out of 10.”
“These are cases that neither me nor my colleagues, who are some of the best doctors out there, maybe we would get it right 2 times out of 10.”
@sama
NEW: Inside Thrive Capital w/ Partner Dr. Nworah Ayogu
Investing in Neuralink, OpenAI, Isomorphic Labs, OpenEvidence, Oscar Health & the next trillion-dollar healthcare companies.
@ThriveCapital manages $65B+ in AUM, having raised $10B+ for Thrive X earlier this year. Healthcare has been part of the firm's DNA since inception, with Josh Kushner incubating Oscar Health alongside Thrive itself.
The firm has incubated ~10 healthcare companies, the majority valued at over $1B, including Oscar Health, Cedar, Rightway & Cadence.
I sat down with Nworah (@nworahayogu), a Harvard-trained, board-certified physician & neuroscientist, former Amazon Clinic GM & Amazon Pharmacy's first Chief Medical Officer, to break down AI's next frontier in medicine.
We cover:
›› Isomorphic Labs: Demis Hassabis, AI-designed drugs & the race to compress drug development from 10 years to 4
›› Neuralink: $9B last funding valuation, brain implants, surgical robotics & restoring independence to patients with paralysis
›› OpenEvidence: $15B valuation, ~$300M annualized revenue & adoption by more than 65% of US physicians. Why AI could create 10X doctors
›› OpenAI: Why healthcare could become AI's most important use case, from clinical reasoning to personalized medicine
Thrive's thesis: Building companies that are world-class in both technology & medicine, with investments spanning Chai Discovery, Formation Bio, Nudge, Fortell, Nourish & more
“Because as a nation, I think we need a 10X nurse a lot more than we need a 10X engineer.”
𝐓𝐈𝐌𝐄𝐒𝐓𝐀𝐌𝐏𝐒
(00:00) Dr. Nworah Ayogu, Partner at Thrive Capital
(01:52) The next AI trade is hiding in biotech
(03:48) How AI designs a new drug
(08:37) 9 out of 10 drugs fail, can AI flip that?
(11:33) How Thrive got into Isomorphic Labs
(14:14) Giving paralyzed veterans their hands back
(20:39) Neuralink is more interesting than SpaceX
(23:21) The hearing aid that broke the rating scale
(30:18) The doctor who built Amazon Health
(33:21) Why AGI makes healthcare the biggest bet
(35:25) One cancer drug outearns every AI lab combined
(37:55) How Lilly became healthcare's first $1T company
(40:04) How Thrive helped OpenAI break into healthcare
(44:13) OpenEvidence: 2/3 of US doctors in 3 years
(46:16) Healthcare is 6x bigger than defense
(48:15) $40T spent, zero gain in life expectancy
(51:43) A custom gene therapy built for one baby
(55:47) Saving Medicare $2.5M a week
(1:04:13) Oscar's comeback from down 95% to up`1 100%
(1:06:19) Why OpenAI is now a giant healthcare provider
Keith Rabois retweeted
Are data centers banned like housing or banned like fentanyl?
Today I signed the data center moratorium legislation.
San Francisco is the national leader in innovation, and that innovation is one important driver of our city’s recovery. We can never take that position for granted. As our city recovers, our administration is working to deliver a recovery that reaches every family and truly supports our communities.
Over the next 45 days, alongside departments and the Board of Supervisors, we will continue the work our administration has already started to develop a thoughtful, responsible framework that allows for the technology infrastructure our hospitals, office buildings, academic institutions, and government rely on while prioritizing community needs, keeping electricity rates low, and protecting the clean water and air our residents deserve.
Keith Rabois retweeted
🚨 Breaking: @EmmanuelMacron has attempted to contact the leaders of the riots in order to surrender
