Anthropic’s S-1/A of 10 November fills in the size of its new equity plans: 1,920,580,692 shares of Class A common stock for the 2026 Equity Incentive Plan, plus the shares carried over from its 2021 plan, and 128,038,713 shares for the 2026 Employee Stock Purchase Plan. The 2 November version left both counts blank.
Together the two base reserves are 2,048,619,405 shares, about 15.7% of the 13,086,672,593 shares the filing expects outstanding after the IPO and the concurrent private placement, by our arithmetic. At the $74 midpoint of the price range, that is about $151.6 billion of stock.
Business Pill · IPO Float
A short explainer on IPO float, the share of a company sold in its listing. It teaches the general idea and does not discuss the equity plans.
The key insight: Anthropic’s 10 November S-1/A sets base reserves of 1,920,580,692 shares for its 2026 Equity Incentive Plan and 128,038,713 for its Employee Stock Purchase Plan, about 15.7% of the 13,086,672,593 shares outstanding after the offering by our arithmetic.
The 2026 Plan becomes effective before the offering, the filing says, and replaces the Amended and Restated 2021 Stock Plan. Its reserve is the 1,920,580,692 base shares, plus shares still available under the 2021 Plan when it ends, plus shares from 2021 Plan awards that would have returned to that plan.
Both plans grow on their own. For the 2026 Plan, the filing says the reserve “will be increased on the first day of each fiscal year beginning with our 2027 fiscal year and ending on (and including) the first day of our 2036 fiscal year”, by the lesser of 5% of the shares outstanding and a number set by the board. The ESPP has the same schedule at 1%, and so does the Donation Matching Plan.
The ESPP is for employees. The filing says the 423 component limits each employee to $25,000 worth of Class A stock a year, measured at the start of an offering, and that offerings can run for up to 27 months.
Anthropic’s 2026 Equity Incentive Plan and Employee Stock Purchase Plan base share reserves, per its S-1/A of 10 November 2026, with the maximum yearly top-ups of 5% and 1% of shares outstanding; the top-ups are our arithmetic on 13,086,672,593 post-offering shares, and the board can set lower numbers.
Our Numbers
On the filing’s 13,086,672,593 post-offering share count, a full 5% increase for the 2026 Plan would be about 654.3 million shares, and a 1% increase for the ESPP about 130.9 million shares, by our arithmetic. Each increase is a ceiling: the filing says the board can set a lower number.
The plan reserves sit next to awards already granted. The filing lists 1,774,342,693 shares issuable on outstanding options at 30 September, with a weighted-average exercise price of $2.91, and 1,026,660,010 shares under RSUs that will not meet their service condition by 19 November. Our RSU tax piece and our piece on the 19 November vesting change cover the RSUs that settle at the IPO.
The same list shows 561,963 Class A shares and 848,882 Class N shares issued after 30 September in connection with acquisitions of privately held companies. The 2 November filing left the Class A count blank. The filing does not name the companies.
The Structural Read
As we read the filing, the reserves are the share budget for future pay: the base counts come first, and from 2027 the 2026 Plan can add up to 5% of outstanding shares a year, subject to the board.
As we read the overhang, the reserves come on top of 1,774,342,693 option shares and 1,026,660,010 unvested RSU shares already granted at 30 September, which the filing lists separately.
Anthropic, PBC, Form S-1/A, 10 November 2026
“The maximum aggregate number of shares that may be issued under our ESPP is 128,038,713 shares of our Class A common stock”
Three Implications
FOR IPO BUYERS The filing excludes the plan reserves from the 13,086,672,593 shares it expects outstanding after the offering.
FOR EMPLOYEES The filing says the ESPP limits each employee to $25,000 worth of Class A stock a year under its 423 component.
FOR THE BOARD The filing says each yearly increase is the lesser of the percentage of outstanding shares and a number set by the board.
The framework records: “It is becoming the first major AI lab actively attempting to define the governance layer of the AI stack.”
As we read it, the equity plans are the capital-structure side of how the lab pays the people who build its models: the share budget is set by plan rules and the board. The framework does not discuss the equity plans.
What Is Not Established
The reserves are a maximum for future awards, not shares granted. The filing does not say how many awards Anthropic plans to grant, when, or to whom. The filing gives no count for the shares carried over from the 2021 Plan. The 15.7% share and the dollar values are our arithmetic on the filing’s counts and the $74 midpoint.
The Great Convergence of Capital, Power, and Geopolitics
This week’s issue: for two years the AI build-out was priced as a supply story, and last week as a credit story. This week it was priced as a permission story, and the answer arrived as a cost, not a ban.
Anthropic’s 10 November S-1/A sets base reserves of 1,920,580,692 shares for its 2026 Equity Incentive Plan and 128,038,713 for its employee stock purchase plan, about 15.7% of the shares outstanding after the offering by our arithmetic, with yearly increases of up to 5% and 1% of outstanding shares from 2027 to 2036.
A note on sourcing. Figures and quotations are from Anthropic’s S-1/A filed with the SEC on 10 November 2026, with comparisons to its S-1/A of 2 November 2026. Percentages and dollar values are our arithmetic. Anthropic was not contacted for this piece.
Gennaro Cuofano is a CRO and tech executive who has worked in AI since late 2015, starting with bringing NLP, natural-language generation, voice and chatbot products to the marketing industry. His background is in law and finance: he holds a Master's degree in Law and an International MBA with an emphasis on corporate finance (LUISS Business School and the University of San Diego, 2012), and worked as a financial analyst at a real-estate investment firm in San Diego and as an assistant controller. His work focuses on business model strategy, business engineering and, more broadly, structural analysis: how companies make money, read from their own filings. He created FourWeekMBA and leads research there and at The Business Engineer, his newsletter on AI and business strategy, with over 95,000 subscribers and more than 1,000 published analyses. His writing has also appeared on Entrepreneur (for example, How to Digitize a Family Business in Europe) and HackerNoon. Find him on LinkedIn and Substack. See how we source.
