Cerebras is public. The staggered lockup ends in November.
Cerebras Systems (Nasdaq: CBRS) IPO'd May 14, 2026 at $185 per share. It surged ~68% on the first day. Then it pulled back. Now about 708 employees are working through a staggered unlock structure — some already had early liquidity, officers are waiting on Q3 earnings, and the outside date for everyone is November 11, 2026. The questions aren't about the stock price. They're about which tranche unlocks when, what taxes you'll owe, and whether to act or wait.1
What happened (as reported)
- IPO: May 14, 2026 — Nasdaq: CBRS. Priced at $185/share; Cerebras raised approximately $5.55 billion, valuing the company at roughly $56 billion — the largest IPO of 2026 at the time.1
- First-day surge. CBRS opened near $350 and reached an all-time high of $386.34 on May 14. The stock closed up approximately 68% from the IPO price. That first-day close above the 33% threshold triggered early unlock provisions for non-executive employees the following day.2
- Post-IPO pullback. The stock reached its all-time low of $160.81 on June 26, 2026. As of September 2026, market capitalization is reported near $49.9 billion — below the $56 billion IPO mark. Stock price and program details may change; verify against current market data and your equity portal.3
- ~708 employees as of September 2026. Cerebras is an unusually small company at this valuation scale — the per-employee equity exposure is significant for a wide range of the workforce.4
This page reports publicly disclosed facts. Cerebras has not endorsed, reviewed, or affiliated with this site. Company names and trademarks belong to their respective owners. Program terms may change — verify everything against your grant documents and company communications.
The staggered lockup schedule
Cerebras does not have a single 180-day lockup date. The structure, as described in the S-1 and analyzed in post-IPO coverage, is tiered by holder type and performance trigger.2
| Tranche | Who it applies to | Trigger / Date | Reported % released |
|---|---|---|---|
| Day-1 unlock | Non-executive employees | May 14, 2026 (first trading day) | ~7.5% of eligible shares |
| Performance unlock | Non-executive employees | May 15, 2026 (triggered because CBRS closed 33%+ above IPO on Day 1) | Additional ~7.5% |
| Q1 earnings unlock | Officers, directors, pre-IPO investors | After first earnings release post-IPO (Q2 FY2026, ~July/August 2026) | ~15% of eligible shares |
| Q2 earnings + fixed dates | All locked holders | Q2 earnings release + fixed dates in August, September, October 2026 | Additional tranches (~60M+ shares total across these events) |
| Outside date (final) | All remaining locked holders | Earlier of: Q3 2026 earnings release OR November 11, 2026 | Remainder |
The exact percentages and eligibility for each tranche depend on your grant type, holder classification, and the company's earnings calendar. Read your grant documents and equity portal — the S-1 lockup section is the authoritative source.
What the November window means in practice
The November 11 outside date is meaningful in two ways. First, it's the deadline: any shares still locked will be released on or before that date (per the terms in the S-1, subject to the Q3 earnings trigger). Second, it's a planning window: if you intend to sell, you want to have made your decisions — how much, at what price threshold, in what accounts — before the window opens, not while the screen is moving.
Officers and certain insiders face additional constraints: they cannot trade while in possession of material nonpublic information, and if they want to sell at unlock, they may need a pre-established 10b5-1 trading plan with its cooling-off period already elapsed. A non-officer who wants to adopt a plan today (September 7) can start selling after the 30-day cooling-off, which puts first eligible trades around early October — in time for October fixed-date tranches and the November window.
RSU settlement taxes
RSUs that settled at the May 14, 2026 IPO created a taxable event under IRC § 83.5 Each settled RSU was valued at the CBRS fair-market value on May 14 — reported around $185 (IPO price) for shares that settled at pricing, or higher for shares that settled at the first-day close if double-trigger conditions were met on that date. That value is ordinary income in your 2026 W-2.
The withholding gap
The IRS requires supplemental withholding at 22% on income up to $1 million and 37% above that. Many Cerebras employees have RSU settlements well into the 35–37% federal bracket, creating a gap that must be funded through estimated payments.
| RSU settlement income | Federal withheld (22%/37%) | Actual federal rate (est.) | Withholding gap | CA at 13.3% |
|---|---|---|---|---|
| $500,000 | $110,000 (22%) | ~$164,500 (37% est.) | ~$54,500 | $66,500 |
| $1,000,000 | $220,000 (22%) | ~$370,000 (37% est.) | ~$150,000 | $133,000 |
| $1,850,000 | $534,500 (22%/$37%) | ~$684,500 (37% est.) | ~$150,000 | $246,000 |
Federal rate shown as simplified flat 37%; actual bracket calculation varies with other income sources. Rates per IRS Rev. Proc. 2025-32 (2026 tax year).5 California does not offer preferential LTCG rates — ordinary and capital gains are taxed at the same rate. Use the RSU settlement tax estimator for your specific numbers.
The basis question
Your basis in CBRS shares is the FMV at settlement — the same amount reported as income. If CBRS is now trading below your settlement price, selling today creates a capital loss (short-term if less than one year from settlement). That loss can offset other capital gains or up to $3,000 of ordinary income per year; excess carries forward. Wash-sale rule warning: buying back substantially identical shares within 30 days before or after the loss sale disallows the loss (IRC § 1091).5
Ongoing RSU vests
Each new RSU vest creates the same withholding-gap dynamic — ordinary income at the vest-date FMV, withheld at 22%. The quarterly estimated payment calendar (Q3 deadline: September 15; Q4 deadline: January 15, 2027) is the tool for staying current. See the estimated taxes guide.
ISO holders: the LTCG clock and QSBS
The one-year LTCG mark
If you exercised ISOs before the IPO, your holding period started at the exercise date — not the IPO date. The tax treatment on a sale depends on whether you satisfy a qualifying disposition: held more than two years from grant date AND more than one year from exercise date. If you exercised years ago, you may already qualify for long-term capital gains rates. If you exercised recently (including same-day exercises at IPO), the one-year mark from your exercise date controls.
For RSU holders whose shares settled at the May 14 IPO, the one-year mark for LTCG treatment on any post-settlement appreciation is May 14, 2027. Between settlement and that date, gains are short-term (ordinary rates). After that date, gains qualify for the preferential 0/15/20% federal LTCG rates (2026 brackets: 15% for most working professionals; 20% + 3.8% NIIT for income above approximately $533,400 single / $600,050 married).5
California does not have preferential LTCG rates. Gains are taxed as ordinary income at up to 13.3% regardless of holding period — a combined California+federal rate near 53% at the top.
QSBS for very early employees
Section 1202 allows employees who received qualified small business stock (QSBS) to exclude gains on sale — potentially up to $10 million (old all-or-nothing regime for pre-July 4, 2025 stock) — if certain conditions are met. Cerebras was founded in 2016 and raised a $27.6 million Series A in 2018.4 The critical threshold is whether the company's gross assets exceeded $75 million at the time your stock was issued. If Cerebras was still under $75 million in gross assets when you received your grant (roughly 2016–2018), and you've held qualifying stock for at least five years, your gain may be partially or fully excludable. This is highly fact-specific: you'll need the company's capitalization history and your grant documents reviewed by a CPA. California does not conform to the Section 1202 exclusion — state tax applies to the full gain regardless.6
Three planning scenarios for November
Scenario A: RSU basis above current price (shares "underwater")
If your RSUs settled at $185 and CBRS is trading below that, you have a paper loss. Selling into the November window creates a short-term capital loss — useful if you have other gains to offset, or if the stock looks fully valued and you'd redeploy proceeds elsewhere. Watch the wash-sale window (30 days before and after the sale) if you want to stay long. If the loss is large enough, it may take years to fully use at $3,000/year against ordinary income.
Scenario B: ISO shares with low basis and large gain
If you exercised ISOs early at a low strike and have significant appreciation, the calculation involves several layers: qualifying vs. disqualifying disposition, AMT preference item from a prior exercise year (if applicable), the QSBS question, and California's ordinary-income-equals-capital-gains treatment. On a $5 million gain, the difference between a planned and unplanned sale can easily reach six figures. Use the ISO AMT estimator for sizing, and see a specialist before the lockup window opens.
Scenario C: Concentration — CBRS is 60%+ of net worth
A 708-person company with a ~$50 billion valuation implies meaningful per-employee paper wealth. For employees with most of their liquid net worth in CBRS, the November window is the first real chance to start diversifying. A planned sell-down over the November and any subsequent windows — rather than a lump-sum sell at one point — allows you to average into a concentration target over time while managing the tax in each year. The concentration glidepath calculator models annual sell-down pacing and after-tax proceeds.
Six steps before November 11
- Map your instruments and tranches. Pull your equity portal: how many shares unlock in each tranche, on what dates, and what type (RSU lot, ISO shares, NQSO shares). Different instruments = different tax treatment.
- Calculate your settlement tax gap. Use the RSU tax estimator to size what you owe vs. what was withheld. If you haven't made Q3 estimated payments (September 15 deadline), check whether a penalty applies. The Q4 deadline (January 15, 2027) is the most important for 2026 income.
- Check your LTCG eligibility date. For RSU lots settled at IPO: LTCG clock starts May 14, 2026. For ISO shares: clock started at exercise. Know the date before selling.
- Assess QSBS eligibility if you're a pre-2019 employee. The $75M gross-asset test is the hardest piece of information to verify — your company's capitalization records control. Ask your equity plan administrator or a CPA who has seen the company's financials.
- Write a concentration policy. Decide your target (e.g., no more than 20% of net worth in a single stock) and the pace at which you'll get there. Commit to the rule before trading opens — it makes execution mechanical, not emotional.
- If you're an officer or director: review 10b5-1 rules now. Officers face a cooling-off period of the later of 90 days or the next 10-Q plus 2 business days, capped at 120 days — adopting today might not clear in time for early windows. A non-officer needs only a 30-day cooling-off. See the 10b5-1 guide for current SEC requirements (Release 33-11138).
The November window is weeks away. Build the plan now.
Get matched with a fee-only fiduciary who has worked post-IPO lockup events — RSU settlement taxes, LTCG timing, QSBS eligibility, concentration glidepath, and 10b5-1 for officers. Free, no obligation. If your window is coming up, say so and we'll prioritize the intro.
Sources
- Cerebras Systems — "Cerebras Systems Announces Pricing of Initial Public Offering" (May 2026) — primary source for IPO price, raise size, and Nasdaq listing.
- Seeking Alpha — "Cerebras: IPO Lockup Comes Fast" (NASDAQ:CBRS) — detailed analysis of the staggered lockup structure, tranche percentages, and earnings-release triggers.
- Yahoo Finance — "Cerebras stock slides after near-70% surge in biggest IPO of 2026" — post-IPO price performance, pullback reporting.
- Wikipedia — Cerebras Systems — founding date (2016), headquarters (Sunnyvale, CA), employee count, and funding history.
- IRS Publication 525 — Taxable and Nontaxable Income and IRC § 83 — ordinary income treatment of RSU settlements; basis and holding-period rules. 2026 brackets and rates per IRS Rev. Proc. 2025-32.
- IRC § 1202 — Small Business Stock Gains Exclusion — QSBS five-year hold requirement, $75M gross-asset threshold, and exclusion percentages. California non-conformity per Cal. Rev. & Tax. Code § 18152.
IPO facts, lockup structure, and stock price data reflect public reporting as of September 2026. Program terms may change — verify against your grant documents, equity portal, and company communications before acting. Tax content uses 2026 rates from IRS Rev. Proc. 2025-32; consult a CPA for your specific situation. This site is not affiliated with, sponsored by, or endorsed by Cerebras Systems.