What's the difference between OpenAI's and Anthropic's S-1 filings?

Both are confidential draft S-1s filed in the same week (Anthropic June 1, 2026; OpenAI June 8, 2026), but the underlying companies are different in three structural ways. First, corporate structure — OpenAI is restructuring from its capped-profit model into a Public Benefit Corporation; Anthropic has been a PBC since founding. Second, revenue mix — OpenAI's ~$30B annualized leans heavily on ChatGPT consumer subscriptions; Anthropic's ~$47B annualized is dominated by enterprise Claude API and recently-announced [TCS-scale partnerships](/answers/tcs-anthropic-global-premier-partnership-explained-june-11-2026/). Third, valuation — Anthropic last priced at $965B post-money; OpenAI's last private mark was $852B post-money but secondary markets imply ~$908B. Anthropic is currently the more valuable private AI company.

Which AI IPO is likely to price first?

Anthropic, most likely. It filed first (June 1, 2026 vs OpenAI's June 8), it is already a Public Benefit Corporation (less restructuring overhead), and its enterprise revenue mix is easier for SEC review and investor diligence than OpenAI's consumer-heavy ChatGPT revenue. Most analyst consensus targets Anthropic IPO in October–November 2026, with OpenAI following in late 2026 or early 2027. See [Anthropic IPO October 2026 timeline](/answers/anthropic-ipo-october-2026-timeline-june-7/). That said, IPO timing is famously unpredictable — both could slip or one could accelerate.

Which is the better IPO investment?

Depends on your thesis. Anthropic has higher disclosed revenue ($47B annualized vs ~$30B), stronger enterprise positioning, and the safety/PBC narrative. OpenAI has the largest consumer brand in AI (ChatGPT), broader product surface (Codex, Sora, Operator), and Microsoft's distribution muscle. For pure-play frontier-model enterprise exposure: Anthropic. For consumer-AI brand and ecosystem reach: OpenAI. For both at scale today, [SPCX (SpaceX/xAI) trading June 12](/answers/spcx-day-one-trading-what-to-expect-june-12-2026/) gives you partial AI exposure now.

What does 'Public Benefit Corporation' actually mean for these IPOs?

A Public Benefit Corporation (PBC) is a for-profit corporate form that legally requires the board to consider a defined public benefit alongside shareholder returns. Both Anthropic and OpenAI (post-restructure) will be PBCs. Practically, this gives the board cover to weigh AI safety considerations against pure profit maximization, which is meaningful for AI labs but can be a tension point at IPO pricing. Investors should expect explicit PBC mission language in both prospectuses and should not expect PBC status to materially constrain commercial decisions in normal operations.

Quick Answer

OpenAI S-1 vs Anthropic S-1: Key Differences You Need to Know (June 2026)

Published: June 11, 2026

OpenAI S-1 vs Anthropic S-1: Key Differences (June 2026)

Two confidential S-1 filings in one week, two very different companies underneath. OpenAI filed June 8, 2026; Anthropic filed June 1, 2026. Here is the honest structural breakdown.

Last verified: June 11, 2026

TL;DR

Detail	Anthropic	OpenAI
S-1 filed	June 1, 2026 (confidential)	June 8, 2026 (confidential)
Last valuation	$965B post-money	$852B post-money
Secondary market	~$1T+ implied	~$908B implied
Annualized revenue	~$47B	~$30B
Corporate structure	PBC (since founding)	Restructuring to PBC
Revenue mix	Enterprise API-heavy	Consumer ChatGPT-heavy
Likely IPO window	Oct–Nov 2026	Late 2026 / early 2027
Headline model	Claude Fable 5 (June 9, 2026)	GPT-5.5

Structural differences

Corporate form

Anthropic has been a Delaware PBC since founding. The S-1 just discloses an existing structure.

OpenAI is restructuring from the original capped-profit OpenAI LP into a Public Benefit Corporation. The S-1 has to walk investors through the restructure, including how Microsoft’s investment converts, how the nonprofit OpenAI parent governs the PBC, and how the public benefit mission is enforceable.

This means OpenAI’s filing has more moving parts. SEC review will be more complex.

Revenue mix

Anthropic — Claude API and enterprise contracts dominate. The June 11, 2026 TCS Global Premier Partnership is emblematic: large multi-year enterprise commitments that look like clean SaaS revenue to investors.

OpenAI — ChatGPT consumer subscriptions are the largest single line. ChatGPT Plus, Pro, Team, Enterprise. Codex, Sora, and Operator add product surface but consumer is the headline. Plus enterprise OpenAI API and Azure OpenAI Service.

Enterprise SaaS revenue typically commands a higher multiple than consumer subscriptions because of stickiness and gross margin. This works in Anthropic’s favor at IPO pricing.

Capital structure

Anthropic — Series H closed at $65B raise, simpler cap table.

OpenAI — Microsoft’s ~$13B+ investment, SoftBank’s recent participation, Saudi PIF, and the capped-profit conversion mechanics make for one of the most complex IPO cap tables in tech history.

Customer concentration

Anthropic — Disclosed multi-year commitments with Amazon (compute partnership), Google Cloud, Deloitte, TCS, and more.

OpenAI — Microsoft is both an investor and the largest commercial partner; ChatGPT consumer base is fragmented across millions of subscribers. The customer concentration story is materially different.

Valuation comparison

Metric	Anthropic	OpenAI	Notes
Last private valuation	$965B	$852B	Both circa Q2 2026
Secondary market implied	~$1T+	~$908B	June 8, 2026
Likely IPO range	$850B–$1.2T	$850B–$1.2T	Subject to market conditions
Revenue (annualized)	$47B	$30B	Anthropic ahead
EV / revenue (at IPO mid)	~22x	~28x	OpenAI carries premium
Likely first-day pop	10–30%	15–40% (brand + scarcity)	Speculative

OpenAI gets a higher revenue multiple because of brand recognition and consumer growth. Anthropic gets credit for higher disclosed revenue and enterprise mix.

What’s likely in each S-1

Both filings will disclose

Detailed model release roadmap and competitive positioning
Compute commitments and capex outlook
Frontier-AI safety risks
Customer concentration
Regulatory exposure (EU AI Act, US executive orders)
Talent retention risk

Anthropic-specific

Constitutional AI methodology and safety research
Public Benefit Corporation mission language
Series H mechanics
TCS, Amazon, Google, Deloitte partnership terms (likely redacted)
Mythos / Fable model class strategy

OpenAI-specific

Capped-profit-to-PBC restructure details
Microsoft commercial agreement (likely partially redacted)
ChatGPT subscriber metrics
Product portfolio breadth (Codex, Sora, Operator, Atlas Browser)
Sora shutdown/relaunch litigation status

Likely IPO timeline

Anthropic — first-filed advantage, simpler corporate structure, enterprise revenue. Most consensus targets October–November 2026.

OpenAI — more SEC review overhead due to restructure. Likely late 2026 or Q1 2027. Sam Altman has said publicly that timing is flexible.

Phase	Anthropic	OpenAI
Confidential filing	June 1, 2026 ✅	June 8, 2026 ✅
Public S-1	Aug–Sep 2026	Sep–Nov 2026
Roadshow	Sep–Oct 2026	Q4 2026 / Q1 2027
Pricing	Oct–Nov 2026	Q4 2026 / Q1 2027

These dates are aspirational and assume normal market conditions.

Investor angles

”I want pure-play frontier AI now”

→ Wait for Anthropic IPO. It is likely first and the cleanest enterprise AI story.

”I want consumer AI brand exposure”

→ Wait for OpenAI IPO. ChatGPT is the strongest consumer AI brand.

”I want exposure today, not in October”

→ SPCX (SpaceX/xAI) trades June 12, 2026. Partial AI exposure (10–15% xAI/Grok) inside a diversified $1.77T entity.

”I want maximum AI optionality, lowest correlation”

→ A basket of all three at IPO. Different vendor concentrations, different consumer/enterprise mixes, different infrastructure stories.

Risks investors should price in

Risk	Anthropic	OpenAI
AI safety regulation	High (story is constitutional)	High
Talent retention	High (smaller team)	High (long-running departures)
Compute cost inflation	Medium	Medium
Model commoditization	Medium	Medium
Customer concentration	Amazon, Google, TCS	Microsoft
Litigation exposure	Lower	Higher (NYT, others)
Restructure execution risk	Low	High (PBC conversion)

What to watch next 30 days

Public S-1 filings (post-confidential review) for both
Anthropic Q3 model release (Opus 4.9 or 5.0 likely)
OpenAI GPT-5.6 or Codex 2.0 — typical late-Q2 / Q3 release cadence
SPCX trading performance (sets sentiment for AI IPO appetite)
Anthropic + TCS first named enterprise win post-partnership

Sources

Anthropic Newsroom: Confidential draft S-1 to SEC (June 1, 2026)
TechCrunch: OpenAI files confidentially for IPO, following Anthropic (June 8, 2026)
Reuters: OpenAI files for US IPO after Anthropic (June 8, 2026)
BBC: OpenAI plans stock market debut (June 9, 2026)
Forbes: Anthropic is now worth almost $1 trillion, more than OpenAI (May 28, 2026)
Morningstar: Anthropic bests OpenAI valuation race, hitting $965B (May 2026)
Crypto Briefing: OpenAI and Anthropic race for IPO, but timing remains uncertain (June 2026)
Business Insider: Anthropic submits S-1, joins IPO race with OpenAI (June 2026)