OpenAI's GPT-5.5 claims to outperform Claude Opus 4.7, released the same week the company closed a $122 billion round at an $852 billion valuation.
OpenAI's launch of GPT-5.5 came wrapped in something unusual for a model release: explicit comparisons to a named rival. The company said its newest model outperforms Anthropic's Claude Opus 4.7, calling out a competitor it has publicly dismissed for months.
The timing was notable. That same week, OpenAI closed a $122 billion funding round at a post-money valuation of $852 billion, its largest raise on record. The company now reports $2 billion in monthly revenue, up from $1 billion per quarter at the end of 2024. With an IPO potentially landing before year-end, holding the benchmark lead has become a commercial necessity, not just a technical one.
GPT-5.5 fits a broader pattern that The Atlantic described this week as a role reversal: OpenAI following Anthropic's lead rather than setting the pace. Anthropic launched Claude Code; OpenAI followed months later with Codex. When Claude Code had a breakout moment in January, OpenAI issued two major Codex updates alongside a press campaign. Earlier this month, OpenAI shipped a Codex version that can operate other applications on a user's desktop, mirroring Anthropic's Claude Cowork tool.
The cybersecurity angle
Alongside GPT-5.5, OpenAI unveiled GPT-5.4-Cyber, a model restricted to vetted users for cybersecurity research. That move followed Anthropic's introduction of Claude Mythos Preview, a model several governments have flagged for its potential to assist attacks on financial systems, power grids, and military infrastructure. Restricted-access cybersecurity models are now a product category both companies occupy at the same time.
The parallel launches reflect how competition between the two firms has expanded beyond consumer chatbots. Both are courting government agencies, large enterprises, and security researchers. Both are navigating the tension between capability and access in the most sensitive corners of artificial intelligence, and neither is conceding ground.
The revenue picture
CNBC reported that ChatGPT now reaches more than 900 million weekly active users. Fidji Simo, OpenAI's applications CEO, told staff the company is "orienting aggressively" toward high-compute enterprise use, aiming to convert that massive consumer base into paid productivity users before a public market debut. Forbes noted that OpenAI has grown revenue at four times the pace of Alphabet and Meta at comparable stages.
Anthropics complicated that narrative faster than most expected. In early April, the company disclosed an annual revenue run rate of $30 billion, a figure that appeared to exceed OpenAI's own rate at that moment. For a firm long seen as the principled, slower-moving alternative to OpenAI's scale strategy, that number shifted perceptions in Silicon Valley. According to The Atlantic, OpenAI has privately become far more attentive to Anthropic than its public posture implies.
What benchmarks cannot settle
The real question is not which model tops today's leaderboard. GPT-5.5 may outperform Claude Opus 4.7 this week; a new Anthropic release could reverse that result before summer. Benchmark churn has become routine across the artificial intelligence industry, with lead changes arriving faster than enterprise procurement cycles. What is less routine is the organizational dynamic underlying them: OpenAI, which started this entire cycle with ChatGPT in late 2022, is now reacting to a company built largely by its own former researchers.
Anthropics was founded in 2021 by former OpenAI employees. The roles have quietly inverted. OpenAI's $852 billion valuation and its coming IPO depend partly on investors believing the company can hold model leadership through an era when a well-funded rival can match it quarter by quarter.
Whether benchmark wins reliably convert into enterprise contracts, when Anthropic competes on nearly identical terms, is the question GPT-5.5 raises but does not answer.
Frequently Asked Questions
What is GPT-5.5?
OpenAI's newest large language model, released in late April 2026. The company claims it outperforms Anthropic's Claude Opus 4.7 on standard benchmarks, though independent third-party evaluations are still emerging.
What is GPT-5.4-Cyber?
A restricted-access model OpenAI released alongside GPT-5.5 for cybersecurity research, available only to a vetted group of users. It parallels Anthropic's Claude Mythos Preview, which carries similar access restrictions.
How large was OpenAI's latest funding round?
OpenAI closed a $122 billion round on April 27, 2026, at a post-money valuation of $852 billion, the largest in the company's history.
Has Anthropic's revenue surpassed OpenAI's?
Anthropics reported a $30 billion annual revenue run rate in early April 2026, which appeared to exceed OpenAI's rate at that point. OpenAI generates $2 billion per month; both figures reflect different moments in time and have not been independently audited.