What happened
Cerebras Systems Inc. (NASDAQ: CBRS) Chief Financial Officer Robert Patrick Komin Jr. sold 32,500 shares on 2026-09-29.
The Form 4 shows a price range of $194.92 to $211.79 per share and total proceeds of about $6.61 million.
The first line shows 1,830 shares at $211.79, and the last line shows 3,000 shares at $194.92.
After the last sale, the filing shows 0 shares held.
The filing says the trades were made under a Rule 10b5-1 trading plan.
It also says that plan was adopted on June 30, 2026.
Key numbers
| Metric | Latest | Change | Source |
|---|---|---|---|
| Shares sold | 32,500 shares | SEC Form 4 | |
| Sale price range | from $194.92 to $211.79 per share | SEC Form 4 | |
| Total sale proceeds | about $6.61 million | SEC Form 4 | |
| Shares held after sale | 0 shares | SEC Form 4 | |
| Share of pre-trade holding sold | 100.0% | Calculated from SEC Form 4 |
Read more: Cerebras Systems (CBRS) stock analysis and investment case
Why it matters
OptimistFi's case is that Cerebras can turn wafer-scale AI systems into a durable alternative to GPU clusters before capital needs dilute the payoff.
This filing weakens that case because the CFO sold every share he reported holding directly.
OptimistFi's calculation shows the 32,500 shares were about 100.0% of his holding before the trade.
That makes this a full exit from his reported direct stake, not a partial trim.
The sale also came in 16 separate fills on the same day.
The Rule 10b5-1 plan is the main caveat because the filing says the sales followed a plan adopted on June 30, 2026.
The price stepped down through the day, from $211.79 on the first line to $194.92 on the last.
That makes the trades less useful as a fresh signal on the business itself.
Even so, the filing leaves a clear ownership baseline at 0 shares.
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What's next
The next dated item in the filing is the June 30, 2026 plan adoption mentioned in the explanation.
The trades themselves were on 2026-09-29, and the report was filed on 2026-09-30.
A later ownership filing would be the cleanest way to check whether the 0-share position still holds.
If it does, this Form 4 remains the latest record of the CFO's direct stake.
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Sources
- SEC Form 4 — Form 4 filed 2026-09-30 for Robert Patrick Komin Jr., with Table I sales and a Rule 10b5-1 statement.
Read the full OptimistFi thesis on Cerebras Systems Inc.: https://optimistfi.com/stocks/CBRS
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The full Cerebras Systems Inc. investment case, its status and the next test to watch live on the Cerebras Systems Inc. thesis page.
Originally published on OptimistFi, evidence-first equity research. More at optimistfi.com.
