On November 10, Anthropic began its roadshow for a US initial public offering that aims to raise up to $64.4 billion at a $1 trillion valuation - a planned public debut that could mark the first listing by a frontier AI lab.
The company’s path to this moment traces back to 2021 and a succession of large funding rounds, product rollouts and legal and regulatory confrontations. Below is a chronological account of key milestones that led to the IPO launch.
Early fundraising and product introductions
- May 2021 - Anthropic, led by siblings Dario Amodei and Daniela Amodei, raised $124 million in a Series A round led by investor and Skype co-founder Jaan Tallinn.
- April 2022 - The company secured $580 million in a Series B financing.
- March 2023 - Anthropic released Claude, a large language model positioned as a direct competitor to offerings from other AI developers.
- May 2023 - The firm raised $450 million from investors including Alphabet’s Google and Spark Capital.
Strategic cloud partnerships and subsequent financing
- September 2023 - Amazon.com announced it would invest up to $4 billion in cash in Anthropic.
- October 2023 - Alphabet’s Google agreed to invest up to $2 billion in Anthropic.
- March 2024 - Anthropic introduced the Claude 3 family of models, saying Claude 3 Opus outperformed competitor models GPT-4 and Gemini 1.0 Ultra on various benchmarks.
Legal and regulatory headwinds
- August 2024 - A class-action lawsuit was filed in California federal court by three authors who alleged Anthropic had used their books and hundreds of thousands of other works to train its Claude chatbot.
Further capital infusions and model advancements
- November 2024 - Amazon invested an additional $4 billion into Anthropic.
- March 2025 - A funding round led by Lightspeed Venture Partners raised $3.5 billion at a $61.5 billion post-money valuation.
- September 2025 - Anthropic’s valuation reached $183 billion after a new $13 billion raise. In the same month the company unveiled Claude 4.5, which it said could code for longer uninterrupted stretches and handle finance and scientific tasks better.
- February 2026 - The company raised $30 billion, more than doubling its valuation to $380 billion.
That February also brought clashes with the US government - then-President Donald Trump said he was directing the government to stop work with Anthropic, and the Pentagon indicated it would declare the startup a supply-chain risk. The company subsequently filed a lawsuit in March 2026 to block the Pentagon from placing it on a national security blacklist.
New models, massive private capital and pre-IPO moves
- April 2026 - Anthropic unveiled Mythos, described as its most advanced model to date and designed with capabilities oriented toward defensive cybersecurity tasks.
- May 2026 - The company raised $65 billion at a valuation of $965 billion.
- June 2026 - Anthropic confidentially filed for a US IPO, positioning itself ahead of a rival in the race to public markets.
- July 2026 - A federal judge in San Francisco approved a $1.5 billion settlement of the class-action lawsuit brought by a group of authors alleging misuse of their books to train Claude.
Late 2026 developments ahead of the roadshow
- August 2026 - Independent music publisher Round Hill Music filed a lawsuit alleging misuse of hundreds of songs to train AI systems. In the same month Anthropic was reported to be projecting 2028 revenue of roughly $190 billion to $200 billion, and its annual revenue run rate had topped $65 billion by the end of July, according to reports citing unnamed sources.
- October 2026 - Reports said some current investors and potential new backers were weighing a lower valuation for Anthropic following recent financial disclosures. The company also announced plans for one of the largest IPOs in history and said it would go public as a public benefit corporation, a structure that requires management to balance broader public interests with profitability goals.
- November 2026 - After formally launching its roadshow, Anthropic disclosed plans to raise up to $64.4 billion in its US IPO.
Context and immediate implications
The roadshow launch represents the latest step in Anthropic’s rapid expansion from a venture-funded research lab into a company pursuing a major public offering. That expansion has been marked by successive financing events that grew valuations and by releases of models the company positioned as competitive with leading AI offerings. It has also included legal challenges from authors and publishers and elevated scrutiny from the US government.
Readers should note that projections and reporting cited in the preceding timeline reflect statements and reported information attributed to Anthropic and unnamed sources; this account presents the sequence of events and reported figures as publicly disclosed during the company’s build-up to its IPO roadshow.