From SpaceX to Saudi Aramco: World's biggest IPOs as Anthropic's blockbuster listing looms

Anthropic's highly anticipated US IPO is anticipated to be one of the largest debuts in history, potentially valuing the AI firm at around $2 trillion. This would mark a significant milestone in the stock market, possibly reshaping key indexes, investor activities, and the overall narrative shaping US equities. In June, Anthropic filed confidentially for a US IPO, indicating plans to raise up to $100 billion that could value the startup at approximately $2 trillion, according to Reuters.

Despite posting a net loss of $42 billion in 2025, Anthropic plans to invest $518 billion in cloud, computing, and infrastructure expenditures over the coming years, as outlined in its IPO prospectus disclosed to Reuters. The company might delay its IPO to post the November US midterm elections, with Reuters stating in September that such a delay is unlikely to significantly impact the offering.

The company has already experienced delays, with marketing set to commence in mid-October at the earliest. In late May, Anthropic raised $65 billion at a post-money valuation of $965 billion, surpassing OpenAI. OpenAI, the company behind AI chatbot ChatGPT, also filed confidentially for a US IPO in June but has ruled out a 2026 public listing due to safety concerns over AI, stating that even a 10% risk of AI causing human extinction by the end of the decade is "unacceptable."

Earlier this month, OpenAI CEO Sam Altman revealed that the company had decided against a stock market listing, citing the need to undertake certain activities more easily as a private entity. OpenAI's IPO could have valued it at up to $1 trillion, as reported by Reuters. SpaceX, founded by Elon Musk, made history with its IPO on June 28, shattering records and surpassing Saudi Aramco's 2019 listing by a large margin to become the biggest initial public offering ever.

With a valuation of $75 billion, the IPO generated proceeds more than double those of Saudi Aramco's record-setting debut. SpaceX shares opened at $160.95 on their first day of trading, bringing its value to $2.1 trillion, although the stock has since declined and closed at $148.68 on September 25, well above its $135 IPO price.