Slaughters and HSF Kramer join legal line-up for Anthropic IPO

Slaughter and May and HSF Kramer are advising on the proposed UK retail offer accompanying Anthropic’s planned US IPO, adding to the legal line-up on the AI developer’s float.

Slaughters is advising Anthropic on the UK retail offer, with corporate partners Simon Tysoe, Harry Hecht and corporate and M&A co-head Richard Smith leading the team.

HSF Kramer is acting for RetailBook, the investment platform facilitating the offer. The team is led by UK head of equity capital markets Michael Jacobs, supported by partners Sarah Ries-Coward and Tom O’Neill.

The proposed offer would allow UK retail investors to participate in the IPO through intermediaries connected to RetailBook’s public offer platform. Its completion is conditional on the wider IPO proceeding, according to RetailBook’s announcement.

Anthropic is expected to make its market debut on the Nasdaq in New York in mid-November.

A boon for the city

The mandates bring two more City firms into a transaction already involving Freshfields and several leading US practices.

Freshfields is advising the IPO underwriters, with a San Francisco team led by global capital markets co-head Sarah Solum and partners Calise Cheng and Phillip Stoup.

Wilson Sonsini is advising Anthropic on the wider IPO, led by chair Rezwan Pavri and corporate department head Allison Spinner. Orrick is handling executive compensation and equity matters, Cleary Gottlieb is advising Anthropic’s long-term benefit trust, and Cravath is acting for the co-founders on certain governance matters.

The IPO filing also reveals the scale of Anthropic’s infrastructure spending. At 30 September 2026, the company had committed to minimum payments of approximately $313.8 billion under non-cancellable purchase agreements, mainly for cloud hosting and other infrastructure services, spanning one to 20 years.

Anthropic also, somewhat alarmingly, warned that a catastrophic AI-related incident could cause losses on such a scale that the insurance industry might not “have sufficient capacity or expertise to underwrite insurance commensurate with such exposure.”

Despite this, the AI giant's upcoming IPO could be the largest in history, with The Wall Street Journal reporting this week that Anthropic had been expected to raise up to $100 billion at a valuation of around $1.5 trillion. However, some investors planning to participate in the deal believe that valuation will need to come down.

Et tu, Harvey?

While this week's global tech sell-off might have dampened enthusiasm slightly, legal AI companies are also eyeing the public markets.

‍Business Insider reported on Thursday that Harvey had held preliminary IPO talks with Latham & Watkins, while Artificial Lawyer subsequently revealed that arch rival Legora was also discussing a potential listing with advisers.