Timeline: Anthropic's path from AI startup to industry-defining IPO

Anthropic on Monday unveiled its IPO filing, moving closer to what could be the first public listing by a frontier AI lab, outlining the technology's potential while also laying bare the risks and costs of developing it.

Here is a look at the road to the planned IPO:

May 2021:


Anthropic, led by siblings Dario Amodei and Daniela Amodei, announces it has raised $124 million in a Series A funding round led by technology investor and Skype co-founder Jaan Tallinn.

Also read: Anthropic unveils its US IPO filing; puts AI ambitions, costs in spotlight

April 2022:

Anthropic raises $580 million in a Series B funding round.

March 2023:

The company releases a large language model, Claude, that competes directly with offerings from OpenAI.

May 2023:

Anthropic raises $450 million from investors including Alphabet's Google and Spark Capital.

September 2023:

Amazon.com announces it will invest up to $4 billion in cash in Anthropic.

October 2023:

Alphabet's Google agrees to invest up to $2 billion in Anthropic.

March 2024:

Anthropic reveals a suite of AI models known as Claude 3. The company says the most capable in the family, Claude 3 Opus, outperforms rival models GPT-4 from OpenAI and Gemini 1.0 Ultra from Google on various benchmarks.

August 2024:

Anthropic is hit with a class-action lawsuit in California federal court by three authors who say it misused their books and hundreds of thousands of others to train its AI-powered chatbot Claude.

November 2024:

Amazon.com pumps another $4 billion into Anthropic.

March 2025:

Anthropic raises $3.5 billion at a $61.5 billion post-money valuation led by Lightspeed Venture Partners.

September 2025:

Anthropic's valuation hits $183 billion post-money, after raising $13 billion in a new round.

September 2025:

Anthropic unveils the Claude 4.5 AI model, saying the newest version can code for longer uninterrupted stretches and handle finance and scientific tasks better.

February 2026:

The company raises $30 billion in a funding round, more than doubling the Claude chatbot maker's valuation to $380 billion.

February 2026:

U.S. President Donald Trump says he is directing the government to stop work with Anthropic, while the Pentagon said it would declare the startup a supply-chain risk.

March 2026:

Anthropic files a lawsuit to block the Pentagon from placing it on a national security blacklist, escalating the AI lab's high-stakes battle with the U.S. military over usage restrictions on its technology.

April 2026:

Anthropic debuts Mythos, its most advanced AI model to date, equipped with sophisticated capabilities and designed for defensive cybersecurity tasks.

May 2026:

Anthropic announces it has raised $65 billion at a post-money valuation of $965 billion.

June 2026:

Anthropic confidentially files for a U.S. IPO, edging ahead of rival OpenAI in a closely watched race to reach public markets.

July 2026:

A federal judge in San Francisco signs off on Anthropic's landmark $1.5 billion settlement of a class-action lawsuit brought by a group of authors who accused it of misusing their books to train its AI chatbot Claude.

August 2026:

Independent music publisher Round Hill Music sues Anthropic and Suno in California federal court, alleging the AI companies misused hundreds of its songs to ​train their systems.

August 2026:

Anthropic is projecting 2028 revenue of ‌roughly $190 billion to $200 billion, Reuters reports, citing sources.

August 2026:

Anthropic's annual revenue run rate topped $65 billion by the end of July, Reuters reports, citing a source.

October 2026:

Reuters reported, citing sources, that some current Anthropic investors and prospective investors in its upcoming IPO are weighing a lower valuation for the AI company after its latest financial disclosures.

October 2026:

Anthropic said it is planning one of the biggest IPOs in history as a public benefit corporation, a legal structure that requires management to balance broader public interests with profitability goals.