It’s my first day at The Wall Street Journal covering startups, VC, AI and more. Confidential tips welcome: kate.clark@wsj.com | Signal: 415-409-9095.

Over the last few weeks, so many people have asked me: if people at Anthropic believe that AI has a meaningful chance of killing us all, why are they building it? @berber_jin1 and I did a deep dive into Anthropic’s relationship with effective altruism to try to explain how doomerism came to be so influential at the company. The tale took us to a group house in San Francisco, “clothing optional” swims in the Bahamas and a co-working space in Berkeley funded by an Anthropic investor’s money that has become a central gathering place for those most worried about the existential risk from AI.wsj.com/tech/ai/ai-safety-ef… via @WSJ

Amazing piece wsj.com/tech/ai/ai-safety-ef…

One of Anthropic’s earliest investors, Jaan Tallinn dances hip-hop and warns about “racing to build a technology that could end humanity.” on.wsj.com/4zjT98T

Bizarre scoop alert: wsj.com/business/hospitality… w/@CaraRLombardo

New - Jeff Bezos has invested $30 billion in Blue Origin over more than a quarter century. The co has raised its first outside funds in a round that includes $2 billion from Bezos, and values the company at $140 billion. @WSJ wsj.com/business/jeff-bezos-…

NEW from @KevinTDugan: New York, one of the largest markets for gambling in the U.S., escalated its fight against prediction markets Thursday by suing Polymarket’s domestic arm, alleging that the bet-on-nearly-everything site was illegally running a gambling operation. wsj.com/us-news/law/ny-sues-…

News -- among the handful of suitors who have expressed interest in acquiring Letterboxd: A24, Sony and....The New York Times Company! Bidding starts at $300 million. w/@LaurenSHirsch nytimes.com/2026/09/24/busin…

In his first on-the-record interview since being fired as CEO of Disney in 2022, Bob Chapek says his predecessor-turned-successor Bob Iger campaigned to undermine him @benfritz wsj.com/business/media/bob-c… via @WSJ

Anthropic leaders have invested in a startup developing technology to detect airborne viruses, amid growing fears that AI could lead to new biological threats. wsj.com/tech/ai/anthropic-le…

Pilgrim, whose device combines air sampling and genomic sequencing to detect biological threats, raised a $25M seed led by Buckley at a $150M valuation (@kateclarktweets / Wall Street Journal) (Visit Techmeme dot com for the link and full context!)

Wrote about Meta’s new Muse AI agent and what hurdles Meta will have to overcome for it to succeed wsj.com/tech/ai/meta-ai-agen…

Andreessen Horowitz has a message for up-and-coming tech talent: Don’t drop out of school to start a company; come do school with us instead. The venture-capital firm is investing $35 million in an unaccredited two-year alternative to traditional college. on.wsj.com/4rnuxci

Great read wsj.com/business/entrepreneu…

NEW: A story full of scoops big and small from @ceostroff and @byneilmehta. > Polymarket removed one of its anti-money-laundering programs during a fraud attack, alarming some staff; CEO Shayne Coplan downplayed risks > Persistent engineering glitches have cost some customers thousands > Internal audio & text messages reveal Coplan’s management style > Some current & former employees & investors are concerned Poly has prioritized growth at all costs > Company is trying to course-correct; eyeing an IPO by the end of 2027 > Talks with Drake fell through; rapper name-dropped Poly in a song anyways; a market on the album saw suspicious trading And more. Gift link below. wsj.com/business/polymarkets…

Sources: Anthropic plans to stage its IPO in November, later than many investors expected; the decision was made before ex-Anthropic researcher Jacob Coxon left (Wall Street Journal) (Visit Techmeme dot com for the link and full context!)

NEW: Anthropic plans to stage its blockbuster initial public offering in November, later than many investors expected. With @cdriebusch and @KateClarkTweets wsj.com/tech/ai/anthropic-sh…

SCOOP: A buyout group led by Bob Iger and Joshua Kushner told potential investors the Lakers’ annual revenue will cross $1.6 billion in a decade, pushing the valuation to at least $30 billion w/@markgmaurer wsj.com/business/media/laker… via @WSJ

End of an era. Warren Buffett is stepping down as chairman of Berkshire Hathaway, the $1 trillion conglomerate that he led for more than six decades wsj.com/finance/warren-buffe… via @WSJ

A bug-hunting independent security research team used Anthropic’s Claude software to gain access to an OpenAI employee’s ChatGPT account, giving them a way to read and suggest changes to the company’s private cache of software. on.wsj.com/4h8vaBP

How Ed Sheeran, a musician known for his crowd-pleasing, inoffensive everyman appeal, landed in this situation illustrates the hazards of planning a lucrative tour at a time of intense geopolitical unrest and cultural division over violent conflicts. on.wsj.com/4AfwGL8