Cerebras draws $52 million in options premium as 19.4 million lock-up shares free up and the stock drops 8%

The most unusual options activity in Wednesday's session came from Cerebras Systems (CBRS). By early afternoon traders had exchanged 74,829 Cerebras option contracts, 3.27 times the 10-day average, carrying about $52.1 million in premium. The shares were down $16.37, or 8.4%, at $178.58 at 3:40 p.m., according to Nasdaq, on a day Investing.com reported the Nasdaq trading about 0.9% higher.

Two causes, both on the record

The first is mechanical. Cerebras's IPO prospectus spreads its lock-up over several releases instead of one date. At 6:00 a.m. Eastern on September 30, up to approximately 19.4 million shares held by directors, officers, employees and other pre-IPO holders became eligible for sale. The same schedule frees another 19.4 million on October 14 and again on October 28, with everything remaining released on the earlier of the second trading day after third-quarter earnings or 180 days after the May 14 prospectus.

The second is a customer question. Investing.com reported that the research firm SemiAnalysis posted that OpenAI's new GPT-6.1 Sol Ultrafast model is being served on Nvidia GPUs rather than Cerebras hardware, while the earlier Ultrafast tier ran on Cerebras. Benzinga noted that neither OpenAI nor Cerebras had publicly confirmed which hardware serves the new tier. The prospectus lists OpenAI among the significant customers whose demand it names as a risk factor.

The numbers behind the headline

The unlock is large next to the float. Robinhood data puts Cerebras's float at about 97.2 million shares, so today's 19.4 million is roughly a fifth of it, and about twice the 9.8 million shares that had changed hands by the time the feed was taken. Eligible does not mean sold: holders can keep their shares, and the prospectus says "up to."

Insiders have filed notice. Form 144 filings on EDGAR show two officers, Dhiraj Mallick (396,000 shares, $77.9 million) and Robert Komin (32,500 shares, $6.4 million), registered proposed sales dated September 29, together about $84.3 million. Co-founder Sean Lie filed one for 120,000 shares on September 25. A Form 144 is a notice of intent, not proof a trade happened.

The options leaned the other way from the stock. Of the 74,829 contracts, 54,904 were calls and 19,925 were puts, about 2.8 calls for every put on a day the shares fell. Together they cover about 7.5 million shares, roughly three quarters of the stock's volume. Options volume does not show who traded or why; calls on a falling stock can be new upside positions, closing trades or one leg of a hedge. Thirty-day implied volatility was 67.7%, which sits at only the 28th percentile of its past-year range, so options were not unusually expensive despite the drop.

The stock is now about 3.5% below its $185 IPO price and about 54% below its $386.34 high of May 14. In its two reports as a public company it moved 19.6% and 11.9%, both lower. The next report is listed for November 19, a date the company has not confirmed.

Wednesday's most unusual options activity

Table figures as of about 2 p.m. ET. EQT was the lopsided one on the put side, with 48,094 puts against 4,558 calls, while Liberty Energy and Genmab ran 14 to 21 times normal volume almost entirely in calls. Several names in the table have congressional trades on file, including Rep. Pete Sessions's disclosed Apple sale of $100,001 to $250,000 dated September 22; those disclosures can lag by up to 45 days and are not a current signal. See our congressional trades tracker.

Sources: options volume, implied volatility and market data via Robinhood; congressional trades via TipRanks (STOCK Act disclosures); filings via SEC EDGAR; Nasdaq; Investing.com; Benzinga. Some data may be delayed. This is market information, not investment advice.