OpenAI Stock vs. Anthropic Stock: Which Nvidia-Backed AI Start-up Would Be the Best IPO Stock to Buy in 2026?

Nvidia (NASDAQ: NVDA) chips and systems are the foundation of the artificial intelligence (AI) boom. Its graphics processing units (GPUs) account for more than 80% of AI accelerator sales, and its full-stack strategy -- meaning it combines its GPUs with adjacent data center hardware and software tools -- gives the company a durable competitive advantage.

At present, owning shares of Nvidia is one way (albeit an indirect method) for investors to get exposure to OpenAI and Anthropic. Both AI start-ups work closely with the chipmaker.

• In September, OpenAI announced plans to deploy at least 10 gigawatts of AI data centers with Nvidia systems. Nvidia also said it would invest $100 billion in the AI start-up.
• In November, Anthropic announced plans to purchase $30 billion of computing capacity from Microsoft Azure (running Nvidia AI systems) and to contract additional capacity up to 1 gigawatt. Nvidia also said it would invest $10 billion in the AI start-up.

However, OpenAI and Anthropic could hold initial public offerings (IPOs) as early as this year, which means investors may soon get direct exposure. Here is why I think OpenAI is the more attractive potential IPO stock based on the latest valuations.

Image source: Getty Images.

1. OpenAI

OpenAI was founded by 11 people (including CEO Sam Altman) in 2015. The company was initially a nonprofit dedicated to artificial intelligence (AI) research, but it formed a for-profit subsidiary in 2019. OpenAI is best known for the generative AI application ChatGPT, powered by the GPT family of large language models. Developers can also integrate the models into custom applications.

Importantly, OpenAI has developed other noteworthy products. GPT Image (the successor to Dall-E) is a generative AI tool that turns text prompts into images. Sora is a generative AI tool that turns text prompts into videos. And Whisper is a generative AI tool that transcribes and translates audio into text.

OpenAI's revenue increased more than 200% to roughly $13 billion in 2025, according to The Information. The company estimates revenue will reach $100 billion in 2028, which implies annualized growth near 100% over the next three years. However, OpenAI does not expect to turn a profit or generate positive free cash flow until 2030.

The Information reports that OpenAI is in talks to raise $100 billion in a funding round that would value the company at $750 billion. That puts its price-to-sales ratio at 58, which is a very expensive multiple. In fact, only one stock in the S&P 500 currently trades at a higher valuation: Palantir at 111 times sales. For context, Nvidia currently trades at 24.6 times sales.

2. Anthropic

Anthropic is an AI research organization founded in 2021 by ex-OpenAI executives Dario Amodei and Daniela Amodei. The company is best known for the generative AI application Claude, which is powered by a family of large language models of the same name. Anthropic also lets developers integrate those models into custom applications.

Anthropic has developed other products. Claude Code is an AI coding tool that can read, write, edit, and debug code in response to natural language prompts. The Model Context Protocol (MCP) is an open standard that lets AI applications (like Claude) access and edit external tools and data. Finally, Cowork is an AI agent that can read, write, and edit files to automate administrative and creative tasks.

The Financial Times reports that Anthropic recently selected a law firm to begin work on its IPO, which could happen as early as 2026. The company is raising funds at a valuation of $350 billion in January 2026. That is nearly double its previous valuation of $183 billion at a funding round in September 2025 but still less than half of OpenAI's $750 billion valuation.

Anthropic's revenue increased 1,100% to $4.5 billion in 2025, according to The Information. The company expects sales to reach $40 billion in 2028, though its bull-case estimate says sales could soar to $70 billion. Importantly, Anthropic anticipates positive free cash flow in 2027, and the company expects to turn a profit for the first time in 2028.

Here is the big picture: Claude is less popular than ChatGPT, but Anthropic believes it will be the first to reach profitability. Nevertheless, the latest valuation of $350 billion implies a price-to-sales ratio of approximately 78, which makes it more expensive than OpenAI. To that end, if both AI start-ups went public today, I would say OpenAI is a better buy, though both stocks would be incredibly expensive.

Trevor Jennewine has positions in Nvidia and Palantir Technologies. The Motley Fool has positions in and recommends Microsoft, Nvidia, and Palantir Technologies. The Motley Fool recommends the following options: long January 2026 $395 calls on Microsoft and short January 2026 $405 calls on Microsoft. The Motley Fool has a disclosure policy.