In a photo obtained by the Financial Times, guests can be seen milling around a male and female model wearing swimming costume-type clothing and lying on a table with boards stacked with sushi on their stomachs.
The event took place in a private dining room at the Mandrake Hotel after the Digital Asset Summit in London earlier this year.
An invitation to the after-party said: "Transcend the ordinary at the Copper experience," adding that "attendees will be able to entertain and explore all five senses".
A Copper spokesperson told the FT the party "was organised by a third-party event planner and open to all delegates as part of the conference".
Hammond, who did not attend the event, became Copper's chairman in January 2023.
Later that year, the digital asset custody and trading startup shed jobs in the face of an uncertain US regulatory environment.
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