OpenAI: ChatGPT, GPT-5.5 & Sora — $852B Valuation, 900M Weekly Users

OpenAI builds ChatGPT (900M+ weekly users), GPT-5.5, o3, and Sora. Closed a $122B round in March 2026 — the largest private funding round in history. $852B valuation. SOC 2, HIPAA.

OpenAI is a San Francisco AI research company founded in 2015 and led by CEO Sam Altman. It builds ChatGPT, which serves over 900 million weekly users, alongside the GPT-5.5 and o3 model families and the OpenAI API. In March 2026 OpenAI closed a $122 billion round at an $852 billion valuation — the largest private funding round in history.

Founded: 2015 · HQ: San Francisco, California, USA · Team: 8,800+ · CEO: Sam Altman · Funding: $180+ billion total raised (13 rounds, 72 investors) · Valuation: $852 billion (March 2026)

About OpenAI

OpenAI was founded in December 2015 in San Francisco as a non-profit artificial intelligence research organization. Its original founding team included Sam Altman (now CEO), Elon Musk (who departed the board in 2018), Ilya Sutskever, Greg Brockman, Wojciech Zaremba, John Schulman, and Andrej Karpathy. The stated mission from the beginning was to ensure that artificial general intelligence (AGI) benefits all of humanity, a goal that has remained the organizing principle of the company even as its organizational structure evolved substantially over the following decade. In 2019, OpenAI transitioned from a pure non-profit to a capped for-profit structure to attract the capital needed for large-scale model training. In 2025, OpenAI restructured into a Public Benefit Corporation (PBC) to simplify its capital structure while retaining a public benefit obligation. This restructuring cleared the path for a potential IPO, which the Wall Street Journal reported in January 2026 is being targeted for Q4 2026. OpenAI's primary consumer product is ChatGPT, which surpassed 900 million weekly active users in early 2026. ChatGPT Plus costs $20 per month and provides access to the latest GPT-5.5 and o3 models. ChatGPT Enterprise is the business tier with SAML SSO, custom data privacy controls, and dedicated capacity. The company also offers an OpenAI API and the OpenAI Realtime API for voice and audio applications. The model portfolio as of May 2026 is headlined by GPT-5.5 Instant, which became the default ChatGPT model in May 2026, replacing GPT-5.3 Instant. The o-series reasoning models — including o3 — handle complex multi-step problems. Sora, OpenAI's text-to-video model, launched publicly in late 2024. Codex serves over 2 million weekly users and is available in enterprise on-premises environments via a Dell partnership. In May 2026, OpenAI launched the OpenAI Deployment Company (DeployCo), a new subsidiary valued at $10 billion pre-money with $4 billion in initial investment from TPG, Bain Capital, SoftBank, Warburg Pincus, and others. DeployCo embeds Forward Deployed Engineers directly into enterprise customers. OpenAI simultaneously acquired Tomoro, an applied AI consulting firm, bringing approximately 150 engineers to the subsidiary at launch. In March 2026, OpenAI closed its largest-ever funding round: $122 billion at a post-money valuation of $852 billion, with Amazon contributing $50 billion, and Nvidia and SoftBank contributing $30 billion each. This is the largest private company funding round in history. Total capital raised across 13 rounds now exceeds $180 billion. OpenAI generates approximately $2 billion in monthly revenue, with annualized revenue estimated at $25 billion as of early 2026. OpenAI's largest strategic investor is Microsoft, which has committed $13 billion in total capital and made Azure the exclusive cloud provider for OpenAI's infrastructure. This arrangement gives Microsoft integration rights to embed OpenAI models across Office 365, Bing, GitHub Copilot, and Azure OpenAI Service. OpenAI employs approximately 8,800 people across its headquarters in San Francisco and offices in New York, London, and Dublin. Compliance certifications include SOC 2 Type II, ISO 27001, GDPR compliance for EU operations, and HIPAA eligibility for healthcare use cases. The company's trust and compliance documentation is available at trust.openai.com. OpenAI faces regulatory scrutiny in the EU and UK over data privacy practices and market dominance concerns related to its Microsoft partnership. The UK's Competition and Markets Authority and several EU member states have raised questions about GDPR compliance in training data collection. OpenAI's commercial strategy centers on expanding ChatGPT's user base, deepening API adoption, developing agentic products, and scaling enterprise deployment through DeployCo.

Mission

To develop artificial general intelligence that is safe and beneficial, ensuring that AI benefits humanity broadly and aligns with human values.

Products

Compliance

SOC 2 Type II, HIPAA, FedRAMP

Links

Website · GitHub · Twitter · LinkedIn · Blog · Docs

Frequently Asked Questions

Who founded OpenAI and when was it established?

OpenAI was founded in December 2015 in San Francisco as a non-profit artificial intelligence research organization. The founding team included Sam Altman (now CEO), Elon Musk (who departed the board in 2018), Ilya Sutskever, Greg Brockman, Wojciech Zaremba, John Schulman, and Andrej Karpathy. The organization was initially funded by a group of technology entrepreneurs including Musk and Altman, who together pledged over $1 billion to the non-profit. OpenAI's original stated mission was to ensure that artificial general intelligence benefits all of humanity, a framing that has remained central to the company's public identity even as its organizational structure shifted. In 2019, it converted to a capped for-profit structure to attract the capital needed for large-scale model training. In 2025 it restructured again into a Public Benefit Corporation as part of a process that could lead to a public offering before 2027. Sam Altman has served as CEO since the company's founding, with the exception of a five-day period in November 2023 when the board removed and then reinstated him.

How many users does ChatGPT have and what does it cost?

ChatGPT reached 200 million weekly active users by late 2024, making it one of the fastest-growing consumer software products in history. The free tier of ChatGPT provides access to GPT-3.5 and limited GPT-4o access with no subscription required. ChatGPT Plus costs $20 per month and gives subscribers priority access to GPT-4o, higher message limits, access to DALL-E image generation, and early access to new features. ChatGPT Enterprise is a business offering with SAML SSO, custom data retention controls, and dedicated capacity; pricing is negotiated per contract and typically scales with seat count and usage volume. OpenAI also offers team plans at $25 per user per month for groups of 2 or more. The ChatGPT mobile apps for iOS and Android are among the top-ranked productivity applications in their respective app stores globally. Revenue from subscriptions and API access combined exceeded $80 billion in annual recurring revenue by early 2026.

What AI models does OpenAI offer through its API?

OpenAI's API as of May 2026 includes several model families with different capability and price profiles. GPT-4o, released in mid-2024, is a natively multimodal model handling text, image, and audio inputs and outputs; it is priced at $2.50 per million input tokens and $10 per million output tokens. The o1 model, released in late 2024, uses extended chain-of-thought reasoning for complex analytical, coding, and mathematical tasks. The o3 model, released in early 2025, significantly advanced benchmark performance including the ARC-AGI reasoning benchmark. GPT-4 Turbo remains available for workloads that were optimized for that model. OpenAI also offers a Realtime API for low-latency voice and audio applications. The company has shifted to a predominantly closed-source approach for its o-series reasoning models. Sora, the text-to-video model, is available through a separate API and consumer interface. Enterprise customers can also access these models through Microsoft Azure OpenAI Service with additional compliance and data residency controls.

How much funding has OpenAI raised and who are its investors?

OpenAI has raised more than $40 billion in total funding across multiple rounds as of May 2026. Microsoft is the largest investor with $13 billion committed in total, making Azure the exclusive cloud infrastructure provider for OpenAI's training and inference workloads. In late 2025, OpenAI was in discussions for an additional round of $50 billion to $100 billion at an implied valuation of $200 billion to $300 billion. The company's revenue has grown substantially, with early 2026 reports indicating more than $80 billion in annual recurring revenue, making it one of the fastest-growing technology companies by revenue ever. An IPO is widely anticipated before 2027, following the 2025 restructuring into a Public Benefit Corporation. Other investors include SoftBank, Sequoia Capital, Thrive Capital, and Andreessen Horowitz. The Microsoft partnership extends beyond equity investment to include joint product development through Azure OpenAI Service and deep integration into Microsoft's Office 365, Bing, and GitHub products.

What happened with the OpenAI board crisis in November 2023?

In November 2023, OpenAI's non-profit board abruptly removed CEO Sam Altman, citing concerns about his candor with board members, without specifying a substantive policy disagreement. Within 24 hours, co-founder Greg Brockman also resigned in solidarity with Altman, and Microsoft announced it would hire both of them to lead a new AI research division. Over the following five days, nearly the entire OpenAI research and engineering staff signed a letter threatening to resign and follow Altman to Microsoft unless the board reversed its decision. The board reversed its decision and reinstated Altman as CEO within five days. Several board members who had voted for the removal subsequently resigned, including Ilya Sutskever (who had initially supported the board but later sided with Altman). The episode exposed deep tensions between OpenAI's non-profit governance structure and the commercial pressures of running a company at its scale. OpenAI subsequently restructured its board to give investors more formal representation and moved toward the 2025 PBC conversion.

What is OpenAI's relationship with Microsoft?

Microsoft has invested $13 billion in total into OpenAI and is the company's exclusive cloud infrastructure partner, hosting all of OpenAI's training and inference workloads on Azure. In return, Microsoft has received deep integration rights to embed OpenAI models across its product portfolio including Office 365 (Copilot features), Bing (AI-powered search), GitHub Copilot (code completion), and Azure OpenAI Service (enterprise API access). The partnership gives Microsoft a significant competitive advantage in enterprise AI tooling and has been central to Microsoft's positioning against Google in cloud and productivity software. Azure OpenAI Service allows Microsoft enterprise customers to access GPT-4o, o1, and other OpenAI models with Microsoft-managed data residency, FedRAMP authorization, and compliance controls. The exclusivity arrangement has also drawn regulatory scrutiny from the UK's Competition and Markets Authority and EU competition authorities, who are examining whether the partnership gives Microsoft disproportionate control over frontier AI model access. The partnership runs through at least 2030 based on publicly available terms.

What compliance certifications does OpenAI hold?

OpenAI holds SOC 2 Type II certification covering its API and enterprise products, with audit reports available to enterprise customers under NDA through the trust portal at trust.openai.com. The company is certified to ISO 27001 for information security management. OpenAI's products are GDPR-compliant for EU operations, with data processing agreements available for enterprise customers. The company offers HIPAA-eligible configurations for healthcare use cases through ChatGPT Enterprise and the API. Azure OpenAI Service, the Microsoft-hosted version of OpenAI's API, additionally holds FedRAMP Authorization at the Moderate level, which is required for many US federal government use cases. These compliance credentials, particularly when accessed through Azure, have been central to OpenAI's growth in regulated enterprise verticals including legal, healthcare, and financial services. OpenAI publishes a detailed trust and compliance documentation hub at trust.openai.com with self-attestation reports and third-party audit summaries.

Is OpenAI planning an IPO and what is its current valuation?

OpenAI is widely expected to pursue an initial public offering before 2027, following its 2025 restructuring from a capped for-profit structure into a Public Benefit Corporation (PBC). The PBC structure simplifies the company's capital table and removes a key structural obstacle to a public offering. In late 2025, OpenAI was reported to be in discussions for a private funding round of $50 billion to $100 billion at an implied valuation of $200 billion to $300 billion. The company reported more than $80 billion in annual recurring revenue by early 2026, which is the financial foundation that would make a public offering attractive to institutional investors. An IPO at these revenue levels would likely place OpenAI among the largest technology company listings in history if it proceeds at the high end of valuation discussions. No specific IPO timeline, exchange, or underwriter has been officially announced as of May 2026. The outcome of ongoing regulatory reviews in the EU and UK could affect the timing and terms of a public offering.