For much of this year investors poured attention into Anthropic and largely overlooked OpenAI. The situation has shifted as OpenAI records a notable increase in buyer interest after unveiling advanced new models and demonstrating strong results with its Codex coding agent.

"Over the past month interest has rebounded sharply," noted Dave McClure, founder and managing partner at Practical Venture Capital, a firm that acquires secondary shares in pre-IPO companies.

Because neither Anthropic nor OpenAI has completed an initial public offering, most investors acquire shares through secondary markets where employees or early backers sell existing stock. These markets remain fragmented and illiquid, so any quoted valuations serve only as estimates rather than live public prices.

"OpenAI encountered numerous negative headlines in the first quarter concerning slower growth, executive departures, Anthropic pulling ahead, and the lawsuit from Elon Musk," McClure explained. "That environment produced sharply reduced demand for OpenAI shares in the early part of the second quarter."

Anthropic continues to lead, attracting roughly five buyers for every two interested in OpenAI shares, according to Glen Anderson, CEO of Rainmaker Securities, a merchant bank specializing in private stock deals.

"A month earlier demand for OpenAI remained modest," he observed. "Anthropic still draws intense interest, yet OpenAI is now attracting bids far more frequently."

OpenAI did not reply to a request for comment.

Optimism about new models

Secondary traders interviewed by Business Insider indicated that OpenAI's recent model launches and the Codex agent have prompted buyers to reconsider the company after a period dominated by Anthropic momentum.

OpenAI previewed its flagship GPT-5.6 Sol model in June and rolled it out more widely this month together with GPT-5.6 Terra and the lower-cost GPT-5.6 Luna. Independent benchmarks rank GPT-5.6 Sol near the top of current systems, although still behind Claude's newest Mythos and Fable releases.

"Buyers are returning to OpenAI," said Adam Crawley, cofounder of Augment, an exchange for pre-IPO technology firms.

Mark Klein, president and CEO of Neostellar, which facilitates access to late-stage startups, highlighted an OpenAI executive's disclosure last week that the company now serves nine million active users across Codex, an autonomous AI agent for complex software engineering tasks, and ChatGPT Work, a newly introduced cloud-based assistant for multi-step professional workflows.

"The speed of this expansion indicates that agentic AI is moving past its initial developer base into wider professional applications," Klein remarked. "Overall, OpenAI appears intent on converting ongoing model gains into lasting usage across coding, research, and knowledge work."

OpenAI is the cheaper stock

Earlier this year Anthropic traded at a clear discount to OpenAI. With that relationship reversed, some traders view OpenAI as a relatively affordable way to balance their Anthropic holdings.

Anthropic reached a $1.2 trillion valuation on secondary markets, as reported last week. OpenAI currently trades at a $933 billion valuation, reflecting a 20 percent rise over the past three months according to Caplight data.

Last week OpenAI CEO Sam Altman accepted personal responsibility for recent challenges while pointing to an upcoming recovery.

"We did not have our best last 12 months ever, which is mostly my fault, but we are about to have our best 12 months to date," he wrote on X.

On the same day, Chinese AI startup Moonshot AI introduced Kimi K3, described as the largest open-weight AI system available worldwide.

"Ongoing pressure from Chinese and open-source rivals will likely constrain OpenAI growth and margins, so the company still faces a difficult path," McClure added.