Cerebras (CBRS) five months after its IPO: below the offer price, $408 million of insider sales, and two customers

Cerebras Systems, which designs wafer-sized chips for artificial intelligence, priced its IPO at $185 a share on May 14, 2026. Trading opened at $350 and the first day closed at $311.07, still the stock’s highest close. On October 5 it closed at $181.55 — 1.9% below the IPO price and 41.6% below the first close — after a low of $166.43 on October 2; by October 9 it was at $164.17. At the October 5 price, the three share classes were worth $43.1 billion, about 63 times revenue over the last twelve months.

A profit only on paper, and a lumpy quarter

The 2025 net profit of $237.8 million did not come from the business: operations lost $145.9 million, and the profit came from $390.7 million of other income, including a one-time $363.3 million gain on the end of a forward contract. In the second quarter of 2026, the first after the IPO, revenue rose 74% from a year earlier but fell 6.9% from the first quarter. The 10-Q shows hardware revenue down 23%, partly because $28.0 million of amortization of “customer warrant assets” is deducted from revenue. The quarter’s $450.5 million loss includes $377.0 million of stock-based compensation, from share awards that vested with the IPO.

Revenue is concentrated. In 2025, MBZUAI accounted for 62% and G42 for 24% — two related parties based in the United Arab Emirates, according to the prospectus; G42 alone had been 85% in 2024. In the second quarter of 2026, three customers the 10-Q does not name made up 34%, 32% and 10% of revenue.

Who held it at the end of June

Nine of the 38 managers held Cerebras on June 30, worth $4.24 billion at that day’s $221 close and 17.9% less at the October 5 price. Being in the first 13F after an IPO does not mean they bought on the market, and the Schedule 13G filings show where the largest stakes came from. At Philippe Laffont’s Coatue, 6.67 million of the 7.01 million shares (95%) were class B, a class that exists only for shareholders from before the IPO. At Brad Gerstner’s Altimeter, 4.64 million of 7.16 million shares (65%) were class B in its August 13G; Cerebras was Altimeter’s second-largest 13F position, after Nvidia. Chase Coleman’s Tiger Global held 3.0 million class A shares by May 15, the day the IPO closed. For the others, the 13F does not say when or how the shares were obtained.

Insiders: $408 million sold, none bought

Since the IPO, insiders filed 59 Form 4s and bought no shares. They sold $408.35 million, of which $345.95 million (85%) went through 10b5-1 trading plans — the founders, chief executive Andrew Feldman and chief technology officer Sean Lie, adopted theirs on May 20, six days after the IPO. Sean Lie sold $193.8 million and Andrew Feldman $64.2 million, nearly all under those plans. Another $26.12 million were sales to cover taxes on vesting shares. Of the $23.49 million sold without a plan, $21.42 million came from the family trust of director Steve Vassallo, after funds of Foundation Capital distributed shares to their investors; his Form 4 lists him as one of the managers of the funds’ general partner. The remaining $12.79 million are lines that give only a price range and no reason, so they cannot be classified either way. The 92 lines with code J are distributions from venture funds to their investors, not sales.

The executives’ Form 4s say their lock-up ends on the second trading day after third-quarter results or on November 9, 2026, whichever comes first. The two biggest one-day drops came after results: −19.6% on June 24, the session after first-quarter results were filed at 4:43 p.m. the day before, and −11.8% on August 13, after the second quarter. The filings do not explain the moves. Daily data is on the Cerebras page. Not investment advice.