Google announced Gemini 4 Argon, its new frontier model, on 30 September. It is rolling out to a set of trusted cyber defenders through Google's Fairwind Program and is not yet generally available. Google says access for developers, enterprises and consumers will follow, starting with paid API customers and Google AI Ultra subscribers.
OpenAI released GPT-6.1 Sol, an upgrade to GPT-6 Sol, on 29 September. It is available to Plus, Pro, Business, Enterprise and Edu users in ChatGPT Work and Codex, and in the API as gpt-6.1-sol at $2 per million input tokens and $10 per million output tokens for prompts up to 272K tokens.
AMD announced on 28 September a definitive agreement to acquire World Labs, an AI model and research lab. The all-stock transaction is valued at about $8.2 billion and is expected to close by the end of 2026, subject to regulatory approvals. Signed, not closed.
Anthropic released Claude Sonnet 5.5, the second model in the Claude 5.5 family, on 28 September. It is available on all platforms, including Amazon Web Services, Google Cloud and Microsoft Azure, priced the same as Sonnet 5 at $2 per million input tokens and $10 per million output tokens.
Anthropic released Claude Opus 5.5, the first model in its Claude 5.5 family, on 22 September. It is available on all platforms, including Amazon Web Services, Google Cloud and Microsoft Azure, at $4 per million input tokens and $20 per million output tokens.
OpenAI released GPT-6 Sol and GPT-6 Luna on 22 September in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise and Edu users, and in the API as gpt-6-sol and gpt-6-luna. API prices per million tokens are $2 input and $10 output for Sol and $0.10 input and $0.50 output for Luna.
SpaceXAI released Grok 4.7 on 21 September. It is available in Cursor, Grok Build and the Grok API, priced from $2 per million input tokens and $6 per million output tokens.
OpenAI introduced ChatGPT for Financial Services on 10 September: a ChatGPT Work experience with built-in financial data from providers such as PitchBook, LSEG News and Crunchbase, plus GPT-6 Astra for research, models and client materials. It was shaped with Morgan Stanley and Evercore and starts with investment banking and equity research.
OpenAI introduced the Agents API on 10 September, in public beta. It runs cloud agents on the harness and infrastructure behind Codex, created with one API call, with the sandbox on OpenAI's side, on your own infrastructure or with a partner.
Awaiting confirmation.
OpenAI released ChatGPT Images 2.5 on 8 September. The company says it turns ideas, sketches and reference photos into more personalized, polished images.
Mistral announced on 8 September that it raised €3 billion in a Series D at a post-money valuation of more than €21 billion. Samsung Electronics led the round, with Scaleup Europe Fund (managed by EQT) and PSG Equity as co-leads.
OpenAI released GPT-6 Astra on 3 September and calls it its most intelligent and aligned model yet, naming computer use, coding, cybersecurity and science as the areas it leads.
NVIDIA announced a definitive agreement to acquire Hugging Face. The 2 September 8-K describes about $11.9 billion to stockholders plus up to about $1.0 billion in retention, a structure of about $12.93 billion. Signed, not closed; expected close in the first half of 2027, subject to regulatory approval.
Google released Gemini 3.8 Flash and Gemini 3.8 Flash Cyber on 2 September.
Meta released Muse Spark 1.3 on 2 September. It is available in Muse Code and the Meta Model API.
Anthropic released Claude Fable 5.1 and Mythos 5.1 on 1 September.
Z.aiAwaiting confirmation.
On 21 August OpenAI updated its GPT-5.6 note to cut Sol API and credit prices by more than 20 percent for about three months. The promotional rate is posted as lasting at least through 21 November 2026.
Stripe agreed to acquire OpenRouter on 19 August. Stripe's newsroom does not disclose a price; press reported figures above $7 billion, including about $7.5 billion. OpenRouter said the transaction is subject to customary closing conditions and expected to close in the coming weeks; no completion has been announced.
Google released Gemini 3.7 Flash on 13 August, three weeks after Gemini 3.6 Flash.
xAI released Grok 4.6 on 12 August.
Anthropic released Claude Opus 5 on 24 July.
Google released Gemini 3.6 Flash on 21 July, with related Flash variants.
xAI released Grok 4.5 on 16 July.
OpenAI made the GPT-5.6 family generally available on 9 July, as Sol, Terra and Luna.
Anthropic released Claude Sonnet 5 on 30 June.
SpaceX / SpaceXAI announced an all-stock acquisition of Anysphere (Cursor) on 16 June. The deal closed on 14 August. SpaceX’s 8-K states an implied equity value of Cursor of $60.0 billion.
Anthropic released Claude Fable 5 on 9 June, with Mythos 5.
Anthropic announced on 28 May that it raised $65 billion in a Series H round at a $965 billion post-money valuation.
Anthropic released Claude Opus 4.8 on 28 May.
Google made Gemini 3.5 Flash generally available on 19 May during Google I/O.
Microsoft and OpenAI announced an amended agreement on 27 April. Microsoft's license to OpenAI IP for models and products through 2032 is now non-exclusive, and OpenAI can serve all its products to customers across any cloud provider. Microsoft remains OpenAI's primary cloud partner.
OpenAI released GPT-5.5 on 23 April.
Anthropic released Claude Opus 4.7 on 16 April.
OpenAI closed its 2026 capital round on 31 March. The company said $122 billion was committed, at a post-money valuation of $852 billion. Amazon, Nvidia and SoftBank were named as participants in contemporaneous reporting.
OpenAI released GPT-5.4 on 5 March, including a native Computer Use API. The snapshot on the company note is dated 2026-03-05.
How we curate
Major releases from the AI companies we follow, multi-billion-dollar deals and other news of comparable impact. Campus updates stay out of the feed.
Company announcements first, then named reporting, each with a date and a source link. An announced deal is not a closed one, and we say which; anything unconfirmed is labeled “Awaiting confirmation”.
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