Insider stock sales exceeded purchases 10-to-1 at US public firms in August

In August, insiders at US public companies sold about $10 of stock for every $1 they bought, based on SEC Form 4 filings, giving August the year’s worst buy-to-sell ratio.

The current month’s 1:3.6 buy-to-sell ratio is less awful than August’s, but it still does not point to a rebound in sentiment.

As prices have climbed, insiders have sold into strength with increasing frequency, disposing of shares at high levels while others buy at those same levels.

On Friday, major stock indexes were less than 3% below their record highs. Over the weekend, Anthropic CEO Dario Amodei drew 70 million social media views with a warning that frontier AI development is moving too quickly to control safely, even within his own company.

Anthropic is raising its probability of doom, or “p(doom),” as it pitches investors on its next fundraising round. Just before Amodei’s doomsday prediction, technology and AI executives had disclosed some of the year’s largest share sales.

Executives dump shares as AI-doom odds climb

Last week, Meta chief product officer Christopher Cox sold $13 million of stock. CrowdStrike chief executive George Kurtz added to the selling wave with $4.2 million in sales on September 9 and 10.

On September 8, Datadog chief executive Olivier Pomel sold $18.6 million. From September 3 to 8, Cloudflare president Michelle Zatlyn sold $27.7 million.

Nvidia director Mark Stevens offloaded 1,848,501 shares valued at roughly $411 million across three trading sessions from August 31 to September 2.

Protos calculated that the sale was 74% larger than the previous Nvidia insider-selling record, the $235 million that Tench Coxe sold in September 2024. Stevens then proposed selling as much as $1 billion more.

The tech executives were part of a broader wave of insider selling across the market. In the first six months of 2026, insiders in all public sectors sold $77.6 billion of shares while buying just $6.9 billion.

That amounts to a buy-to-sell ratio of about 1:11 in the first half of 2026, worse than the already poor 1:9.7 ratio seen in the first half of 2025.

Over six months, Meta insiders sold 150 times and bought zero.

‘A swarm could be capable of taking over the entire internet’

If Anthropic’s CEO is right, it was probably a good idea to sell before the end times.

Over the weekend, Amodei wrote, “It’s my worry that in 6-12 months such a swarm could be capable of taking over the entire internet with a persistent botnet (potentially causing hundreds of billions of dollars in damage),” in an essay that had some influencers prematurely calling for a 10% drop in AI stocks.

Amodei didn’t specifically warn about stock prices, but he pleaded, “We must slow the pace at which we improve the capabilities of AI models… Left unchecked, it could outrun our ability to understand and control these systems.”

We Must Pace the Frontier: I’ve written a new essay on why the AI industry should slow down, with a three-part plan for doing so.

Anthropic is unilaterally committing to the first of these steps. We’ll provide third-party evaluators with permanent, employee-level access to our…

— Dario Amodei (@DarioAmodei) September 12, 2026

Back in July, Protos had flagged this pattern; at that point, Meta insiders had just completed six consecutive months of 150 sales and no purchases.

In fairness, none of the executives named in this article violated insider-trading rules. Their sales were disclosed in public SEC filings, and they have the legal right to cash out.

Even so, the people with the clearest view inside these companies are swapping equity for cash at nearly 10 times the pace of their purchases last month.

The sales also came weeks before the warning from Dario Amodei, the second-most prominent voice in AI behind Sam Altman, that the technology might somehow take over the internet “in 6-12 months.”