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Last updated: October 2026. Anthropic's IPO terms here come from reporting ahead of its public S-1. I'll update this post when the filing lands.
Anthropic hasn't published its lockup. Reporting says most holders will wait longer than the standard 180 days, possibly until mid-2027, with a limited sale allowed in the IPO itself and rank-and-file employees selling only through preset 10b5-1 plans. The public S-1 should confirm the terms.
If you work at Anthropic, you've probably done the math on your vested equity more than once this fall. The harder question is when any of it turns into money you can spend, and the answer depends on a document nobody outside the deal has read yet. This post separates what's confirmed from what's only been reported, then shows how to plan a sale you may not be allowed to make until next summer.
| Item | Status |
|---|---|
| Confidential draft S-1 submitted to the SEC on June 1, 2026 | Confirmed (Anthropic) |
| Listing on Nasdaq | Reported (Bloomberg) |
| Roadshow as soon as the week of November 9, trading before Thanksgiving (November 26) | Reported (Bloomberg) |
| Public S-1 expected in late October, since it must be on file 15 days before the roadshow | Expected |
| Lockup longer than 180 days for at least some holders, possibly until mid-2027 | Reported (The Information) |
| Existing holders may sell a limited amount in the IPO itself, partly to cover taxes | Reported (The Information) |
| Rank-and-file employees may be required to sell only through 10b5-1 plans | Reported (The Information) |
Nothing in the "reported" rows is final. Deal terms change between the confidential draft and the public filing all the time.
What Is an IPO Lockup Period?
A lockup is a contract in which employees, founders and early investors agree not to sell their shares for a set period after the IPO, usually 180 days. The underwriting banks require it so that a flood of insider shares doesn't hit the market while the new stock is still finding its price.
The lockup follows the shares, so leaving the company during the lockup doesn't free them. (What happens to grants that haven't vested yet when you leave is a separate question, covered in what happens to unvested RSUs when you quit.)
How Long Will the Anthropic Lockup Be?
Nobody outside the deal knows yet. The Information reported in August 2026 that the lockup would run longer than 180 days for at least some holders, possibly until mid-2027, and the S-1 will settle it.
"Longer" doesn't have to mean one long wall. Recent IPOs have used staged releases, where slices of stock unlock early based on dates, earnings or the share price:
- Airbnb let holders sell up to 15% of their shares in the first seven trading days.
- Snowflake released 25% at day 91.
- CoreWeave released part of its lockup early in 2025. More than $1 billion of insider selling followed, and the stock fell 35% over two sessions.
- SpaceX, which listed in June 2026, locked insiders up for 366 days and everyone else for 180, with tranches unlocking along the way: 20% after Q2 earnings, price-triggered releases, 7% slices on set days and about 28% after Q3 earnings. Full expiry for non-insiders is December 8, 2026.
SpaceX is the comparison to watch. Axios's Dan Primack wrote on September 30 that SpaceX "gave the IPO playbook" to Anthropic, so a split between insiders and everyone else, with staged releases, wouldn't be a surprise.
Holding Anthropic RSUs and a quota?
Bring your comp plan and grant docs. We'll map the IPO-year tax bill before it lands.
Build Your Commission PlanCan Anthropic Employees Sell Shares in the IPO?
Possibly, in a limited amount. According to the same reporting, existing holders may be allowed to sell some shares in the offering itself, partly so they can pay taxes on equity that vests at the listing. How much, and who qualifies, is unknown until the S-1 is public.
If that allowance happens, treat it as your tax money first. A small sale in November that covers the April bill is worth more than a bigger sale in mid-2027 at a price nobody can predict.
Can I Sell Anthropic Shares Before the IPO?
Only through a tender Anthropic runs. On May 11, 2026, the company declared that any transfer without board approval is void, including sales to SPVs, and it named eight secondary platforms in the notice. Until the listing, tenders are the only exit.
The most recent tender is a warning sign. It closed in April below its $6 billion target, according to Bloomberg, because employees chose to hold. Plenty of people inside the company had a chance to diversify at a $350 billion valuation and passed. That's a reasonable bet on the company and a large bet on one stock, and it means many employees will reach the lockup with most of their net worth in Anthropic. The Anthropic equity guide for sales reps walks through how that concentration interacts with commission income.
What Is a 10b5-1 Plan?
A 10b5-1 plan is a written instruction to a broker, set up while you have no inside information, that says when and how much stock to sell. Once it's running, trades happen automatically, even during blackout periods when you otherwise couldn't trade. Companies like these plans because they protect employees from insider trading claims.
The catch is the waiting period. The SEC's 2022 rule amendments set cooling-off periods between adopting a plan and its first trade:
| Who you are | Cooling-off period |
|---|---|
| Employees who aren't officers or directors | 30 days |
| Officers and directors | The later of 90 days or 2 business days after the next 10-Q or 10-K, capped at 120 days |
The same rules generally bar running overlapping plans and limit single-trade plans to one per 12 months. Most companies also only let you adopt or change a plan during an open trading window. If Anthropic requires 10b5-1 plans for rank-and-file staff, as reported, you'll need to have a plan written and adopted at least 30 days before the first day you want a share sold.
Why Do You Have to Decide How to Sell Before You Can?
Because the plan has to exist before the lockup ends, you'll be writing your selling rules without knowing the price you'll get. Forbes put it plainly in September: "employees may have to decide how to sell before they can."
That sounds like a disadvantage, but in practice it helps. Nobody makes good selling decisions while watching their net worth move six figures in an afternoon, and I saw that up close in sales, where a great quarter made everyone feel like it would repeat. A plan written in advance takes the emotion out, as long as the rules are price-insensitive: a share count per window, with no "only sell above $X" trigger that leaves you holding everything if the stock drops.
Suppose an AE nets shares worth $653,562 after withholding on an IPO-day vest, owes another $111,313 in April (the math is in the next section), and wants Anthropic to end up as about a quarter of their net worth. A simple rule set might look like this:
| Window | Rule | Share of original position sold |
|---|---|---|
| First open window | Sell enough to cover the tax gap ($111,313 ÷ $653,562) | 17% |
| Next four quarterly windows | Sell a fixed 14.5% of the original share count each time | 58% |
| After that | Hold the remainder, revisit yearly | 25% kept |
The percentages matter less than writing them down. If you plan to give shares to charity, carve those out before you set the plan; the Anthropic donation match post covers why long-held shares make a better gift than cash.
After the lockup, you also live inside the company's trading windows. Employees covered by the insider trading policy can usually trade only during open windows, which typically start a day or two after quarterly earnings and close a few weeks before quarter-end. That's another reason the plan helps: it keeps selling on schedule when the window is shut.
How Does the Lockup Collide With Your RSU Tax Bill?
Your double-trigger RSUs become taxable on IPO day, but the lockup may stop you from selling until 2027. Every time-vested RSU turns into W-2 ordinary income at the listing price, all in one tax year, and federal withholding on it is 22% up to $1 million of supplemental wages (37% above that) under IRS Publication 15.
Here's a hypothetical single AE with a $112,400 base, $75,000 in commissions and $837,900 of RSUs vesting at a November IPO. Taxable income goes from $171,300 to $1,009,200 after the $16,100 standard deduction.
| Slice of the $837,900 vest | Bracket | Federal tax |
|---|---|---|
| $30,475 (to $201,775) | 24% | $7,314 |
| $54,450 (to $256,225) | 32% | $17,424 |
| $384,375 (to $640,600) | 35% | $134,531 |
| $368,600 (to $1,009,200) | 37% | $136,382 |
| Total federal tax on the vest | $295,651 | |
| Withheld at 22% | $184,338 | |
| Gap owed April 15, 2027 | $111,313 |
That's federal income tax only, before state tax or the 0.9% Additional Medicare Tax. If the lockup runs to mid-2027, the $111,313 is due before this rep can sell a single share. Paying 110% of your 2025 tax through withholding protects you from the underpayment penalty under IRS Publication 505, but it doesn't make the bill smaller. The full breakdown, including California, is in Anthropic RSU tax: the April 2027 problem.
For sales reps, commission checks keep coming during the lockup, and they're the obvious place to build the April cash. Run those through one high-yield savings reserve instead of spending them as they land; the free income smoothing resources show the setup (Get Resources).
Owe tax in April on shares you can't sell until summer?
We'll build the 10b5-1 rules and the cash plan for the tax bill together.
Build Your Commission PlanWhat Happens to the Stock Price When a Lockup Expires?
It often falls, sometimes hard. When the lockup ends, a large block of shares becomes sellable at once, and a lot of holders have been waiting months to diversify.
| Company | IPO price | Around lockup expiry |
|---|---|---|
| Uber (2019) | $45 | About $25.58 |
| Rivian (2021) | $78 | About $23 |
| Figma (2025) | $33 (peaked near $143) | $22.51 |
| Reddit (2024) | $34 | About $50 |
| SpaceX (2026) | $135 | Rose about 6% after 900 million shares unlocked |
Uber employees paid tax on RSUs valued near $45 and could first sell near $27. Figma holders watched about 80% of the peak value disappear before they could sell. Reddit and SpaceX show it isn't automatic, but the pattern that repeats is employees taxed at a high price and selling at a lower one, which is the core problem behind double-trigger RSUs and IPO taxes. For how RSUs fit with options and other grants, start with the equity compensation hub.
Want your selling rules written before the S-1 drops?
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Build Your Commission PlanFrequently Asked Questions
How long is the Anthropic IPO lockup?
Anthropic hasn't published its lockup terms yet. Reporting from The Information in August 2026 says the lockup will run longer than the standard 180 days for at least some holders, possibly until mid-2027. The public S-1, expected in late October 2026, should state the official terms.
When can Anthropic employees sell stock?
Right now, only through company-run tenders, because Anthropic declared unapproved transfers void in May 2026. After the IPO, reporting says employees may get a limited sale in the offering itself, then wait out a lockup that could run into mid-2027, possibly selling only through preset 10b5-1 plans.
Can Anthropic employees sell shares in the IPO?
Possibly, in a limited amount. Reporting says existing holders may be allowed to sell some shares in the IPO itself, partly so they can cover taxes on equity that vests at the listing. Anthropic hasn't confirmed this, and the size of any allowance is unknown until the S-1 is public.
What is a 10b5-1 plan?
A 10b5-1 plan is a written trading plan you set up in advance, while you have no inside information, that tells a broker when and how much stock to sell. Under SEC rules, employees who aren't officers or directors must wait 30 days after adopting a plan before the first trade.
What happens to the stock price when a lockup expires?
It often drops, because a large block of shares becomes sellable at once. Uber went from a $45 IPO price to about $25.58 near its lockup expiry, and Rivian fell from $78 to about $23. Reddit went the other way, rising from $34 to about $50.
Can I sell Anthropic shares before the IPO?
Only in a company-approved tender. On May 11, 2026, Anthropic said any transfer without board approval is void, including sales to SPVs and secondary platforms. That leaves tenders and the IPO as the only exits for employees.
Do I owe tax on Anthropic RSUs if I can't sell during the lockup?
Yes. Double-trigger RSUs become ordinary income on the IPO date at that day's value, whether or not the lockup lets you sell. A November 2026 vest creates a bill due April 15, 2027, which could arrive before a mid-2027 lockup ends.
Update Log
- October 2026: Published based on pre-S-1 reporting.
This article is for educational purposes and isn't tax or legal advice. Anthropic has not publicly confirmed its IPO terms; details are based on reporting as of October 2026.
