Is OpenAI filing for IPO in June 2026?

Per CNBC reporting on May 28, 2026, OpenAI is preparing to file its confidential IPO prospectus 'in the coming days or weeks.' The filing is confidential under the JOBS Act, so the prospectus contents won't be public immediately. A confidential filing typically precedes a public S-1 by 2-3 months, which in turn precedes a pricing roadshow by another 1-2 months. Realistic timing for an OpenAI public market debut: Q4 2026 or early 2027 if the filing goes smoothly.

Will OpenAI or Anthropic IPO first?

OpenAI is significantly further along the IPO process as of June 2026. The confidential filing reported by CNBC for the 'coming weeks' suggests OpenAI may go public 6-12 months before Anthropic. That said, IPO timing is heavily market-dependent — if public markets soften, both companies can delay. If OpenAI prices well, Anthropic accelerates. Base case in June 2026: OpenAI prices Q4 2026 or Q1 2027; Anthropic follows 6-12 months later.

Should I buy shares of OpenAI or Anthropic via secondary markets?

Both companies trade on secondary markets (Forge, Hiive, EquityZen, etc.) with significant friction — accredited-investor requirements, minimums of $100K+, and prices that move opportunistically. Pre-IPO secondary buying carries meaningful risk: discount-to-last-round may evaporate if the IPO prices lower, and lockups limit liquidity. For most investors, waiting for the public market debut and managing position size from there is the safer path. This is not investment advice.

Quick Answer

OpenAI IPO Filing vs Anthropic Series H: Which AI Giant Prices First? (June 2026)

Q: When will Anthropic IPO?

Anthropic has not publicly committed to an IPO date. The $65B Series H at $965B post-money (May 28, 2026) is widely reported as 'likely the last private round before IPO' (per TechCrunch and NYT). Crossover-fund participation (Fidelity, T. Rowe Price, Capital Group, Baillie Gifford) is the strongest possible signal that Anthropic is IPO-ready, since these are the same funds that buy at IPO. Most likely Anthropic IPO timing: 2027, possibly H1.

Published: June 1, 2026

OpenAI IPO Filing vs Anthropic Series H: Which AI Giant Prices First? (June 2026)

On May 28, 2026, two major financial events happened on the same day: Anthropic closed its $65 billion Series H at a $965 billion post-money valuation, and CNBC reported that OpenAI is preparing to file its confidential IPO prospectus “in coming days or weeks.”

That’s the public-markets endgame for AI’s two biggest private companies. Here’s the IPO race, what’s known, what’s likely, and what it means for builders and investors.

Last verified: June 1, 2026.

TL;DR

	OpenAI	Anthropic
Latest valuation	$852B (March 2026 round)	$965B (May 2026 Series H)
IPO status (June 1, 2026)	Confidential filing imminent	Series H positioning for IPO
Realistic public debut window	Q4 2026 – Q1 2027	2027, likely H1
Why ahead	Multi-product ecosystem, ChatGPT distribution, larger revenue base	Higher recent valuation, crossover fund participation
Microsoft / Big Tech ties	Microsoft (Azure, M365 Copilot)	Amazon (AWS), Google (Anthropic partner)
Flagship model (June 2026)	GPT-5.5; GPT-5.6 expected by June 30	Claude Opus 4.8 (May 28, 2026)

What CNBC actually reported

From CNBC’s May 28, 2026 piece “Anthropic tops OpenAI as most valuable AI startup, nears $1 trillion valuation in latest round”:

“OpenAI is preparing to file its confidential IPO prospectus in the coming days or weeks, CNBC has confirmed.”

Three things to unpack:

“Confidential” filing is normal under the JOBS Act for emerging growth companies. The prospectus is submitted to the SEC but not publicly posted. Companies use this to get feedback from the SEC before publishing the public S-1.
“Coming days or weeks” is corporate-comms ambiguity. Could mean the filing is already drafted and going out in 1-2 weeks. Could mean another month.
Confidential ≠ imminent public debut. Even after a confidential filing, the typical timeline is:
- Confidential filing
- 2–3 months of back-and-forth with the SEC
- Public S-1 filing (this is when prospectus contents become public)
- 4–6 week roadshow
- Pricing and first day of trading

So a confidential filing in June 2026 most likely means public market debut in Q4 2026 or early 2027, assuming no major hiccups.

What Anthropic’s Series H signals

Anthropic’s $65B Series H wasn’t just a fundraise — it was a pre-IPO staging round. Three structural signals:

1. Crossover-fund participation. Fidelity, T. Rowe Price, Capital Group, Baillie Gifford are all on the cap table now. These are the funds that buy at IPO. Having them already on board:

Reduces IPO execution risk (anchor demand pre-built)
Sets a price floor for the IPO valuation
Signals that public-market investors believe in the story

2. Round size. $65 billion is way more than Anthropic needed for working capital. The excess is essentially a pre-funded balance sheet for the IPO — Anthropic doesn’t have to file under capital pressure.

3. Multiple investors with different time horizons. Sovereign wealth (GIC), private equity (Blackstone, Brookfield), tech-focused (Coatue, Greenoaks), crossover, strategics (MGX). This is exactly the cap table you’d build if you were planning for a 12-24 month IPO window with optionality on timing.

The NYT and TechCrunch both characterized the Series H as “the last private round before IPO.” That’s the consensus read.

Why OpenAI is ahead in the IPO race

1. Started earlier. OpenAI’s pre-IPO preparation has been visible since 2024 (hiring a CFO, building investor relations, transitioning the corporate structure). Anthropic’s pre-IPO posture only became overt in early 2026.

2. Larger immediate revenue. OpenAI’s run-rate revenue at end of 2025 was reportedly meaningfully ahead of Anthropic’s, though Anthropic has been growing faster.

3. Microsoft anchor. Microsoft as a strategic investor and primary distribution partner gives OpenAI an obvious comparable in public markets and a baseline analyst story.

4. Multi-product diversification. ChatGPT (consumer), Codex (developer), Sora (creator), Workspace Agents (enterprise) — OpenAI has the diversified-revenue story that public market analysts demand. Anthropic is more concentrated in Claude API and Claude Code.

Why Anthropic might catch up faster than expected

1. Higher recent valuation. $965B vs $852B on paper. If Anthropic IPOs second but at a higher absolute valuation, market cap comparison still favors Anthropic.

2. Coding-agent dominance. Claude Opus 4.8 is the SWE-bench Verified leader (88.6%). Claude Code with dynamic workflows is the most mature autonomous coding stack. Developer tools are a category where public markets reward strong moats.

3. Lower regulatory risk. Anthropic has been more conservative on cyber capabilities (Mythos still restricted access), more aligned-by-default, and more explicit about safety. That reduces tail risk for public investors worried about regulatory action.

4. Ad-free commitment. Anthropic publicly committed (May 27, 2026) to never inject ads into Claude. That’s a long-term gross-margin signal that contrasts favorably with OpenAI’s ChatGPT ad experiments.

What this means for builders

Short answer: mostly nothing changes today. IPO timing doesn’t affect API quality, pricing, or release cadence in the short run. But it does shift a few things on the margin:

1. Pricing stability. Public companies are more sensitive to short-term gross-margin pressure than private companies. Expect both OpenAI and Anthropic to be less price-aggressive post-IPO. Gemini 3.5 Flash and DeepSeek V4 will keep getting price pressure; Claude and ChatGPT prices will stabilize.

2. Product velocity. Public companies sometimes slow product cadence to manage investor expectations. Watch whether OpenAI’s GPT-5.6 release (expected by June 30) and Claude’s pace continues post-filing.

3. Customer concentration disclosures. S-1 filings will reveal big customer concentration. Expect press cycles about who depends on whom (US government, Microsoft, Amazon, individual large customers).

4. Pre-IPO PR push. Expect more enterprise wins announced publicly, more partnerships, more big-customer case studies. Marketing budgets will spike.

What this means for investors (general thoughts, not advice)

If you’re an accredited investor considering secondary purchases:

Forge, Hiive, EquityZen all list both OpenAI and Anthropic shares at moving prices
Friction is high — accredited-only, $100K+ minimums, multi-week settlement, ROFR holds
Lockups matter — pre-IPO shares typically have 180-day post-IPO lockups, sometimes longer
Price-to-last-round discount can be misleading — both companies have re-marked up significantly since their last priced rounds

For most retail investors, waiting for the public market debut is the lower-risk path. Both companies are large enough that you’ll have liquidity at IPO and beyond.

Sources

CNBC: Anthropic tops OpenAI as most valuable AI startup, nears $1 trillion valuation — confidential filing report
Anthropic: Series H announcement — official $65B detail
TechCrunch: Anthropic raises $65B, nears $1T valuation ahead of IPO
NYT: Anthropic Tops OpenAI to Become the World’s Most Valuable A.I. Start-Up
Bloomberg: Anthropic Eclipses OpenAI With $965 Billion Valuation

Bottom line

OpenAI is ahead in the IPO race and will most likely price first — Q4 2026 or Q1 2027. Anthropic follows 6-12 months later, possibly at a higher absolute valuation. For builders, the practical impact is small in the short term but expect pricing stabilization and louder PR cycles. For investors, watch the public filings closely and don’t confuse paper valuations with realized prices.