Analysis:From SpaceX to Anthropic, markets have a new playbook for mega-share debuts

Anthropic’s expected IPO is set to follow a playbook shaped by SpaceX’s June listing: major index providers plan to add the company to key benchmarks within days, bringing substantial buying from funds that track those indexes. That matters because early share prices may be driven as much by investors preparing for mandatory index purchases as by demand based on the company’s prospects.

Anthropic aims to raise up to $64.4 billion by selling 825 million shares at $70 to $78 each, valuing it at up to $1.4 trillion; the offering represents about 6 per cent of its outstanding shares. Index-tracking funds could account for roughly $19 billion of demand, while retail buyers are also being offered a larger-than-usual allocation. SpaceX shares rose 50 per cent by their third trading day before later easing, but Anthropic’s path may differ because some employees can sell on day one and a separate $26 billion private sale has no lock-up.