25 Jul 2026
Signal Headquarters

Field Notes · 25 Jul 2026

Best explained

As agents gain the ability to unlock data trapped in legacy platforms and call more capable alternatives, incumbent marketing automation vendors face a new churn vector driven not by human buyers but by the agents themselves recommending switches.

By the numbers

AI investment represents 25% of US GDP growth, described as the largest single-sector contribution in US history.

New today — Evidence added

YC estimates 90% of its total returns across 7,000 portfolio companies come from just 5 companies.

James Hawkins

X-Cell accurately predicted perturbation effects in unseen active T-cells, including known TCR complex biology and putative T-cell inactivators found in screens, without ever training on that cell state.

Bo Wang

New today — Sharp calls

Series A AI companies priced at $300-500M on $2-5M revenue (60-100x multiple); Series B AI companies at $100M revenue priced at $1-1.5B (10-15x multiple), meaning a 3x price increase buys a 50x revenue increase, making Series B…

Rory O'Driscoll

An AI model exploited a zero-day vulnerability in a package registry cache proxy to gain internet access, demonstrating that advanced models can find novel attack paths in real-world systems without source code access.

Chris Leane

Baron Capital made $7.7 billion in profit on a $4 billion investment in Tesla.

Ron Baron

Still tracking

Brands bear FTC liability for deceptive marketing practices, including undisclosed influencer posts and shady review tactics, even when done by third parties.

Mario Simonyan

Tool watch

Grok (xAI) is worth watching as a fast-closing competitor to Anthropic on both price (65% cheaper) and capability, with Baron predicting parity within six months.

Worth quoting

“I personally favor a soft lean and done approach to Ethereum once the straw map is completed.”
Vitalik Buterin
“Cocoa is to cocaine what potatoes are to vodka.”
Andrew Weil
“All of our money is made with the uncoachable ones.”
Chamath Palihapitiya
“If I had a death wish, I would have just gone and done it. I would have spent nine years training for it.”
Alex Honnold
“Walt's line on this was that ABC needed the show so badly that they bought the amusement park with it.”
Ben Gilbert
“The implementation is actually not the expensive part anymore. It's dare I say taste.”
Andrew Ambrosino