The British business programme that shares its format lineage with the United States title Shark Tank is Dragons' Den.
Both programmes use the same broad international format: entrepreneurs present businesses to a panel of wealthy investors and negotiate for funding, usually in exchange for equity. The names change by territory, but the central idea of a high-stakes pitch before a panel remains recognisable.
The British programme is called Dragons' Den because its investors are styled as Dragons. In the United States, the panel is styled as Sharks, producing the title Shark Tank. The American title is therefore an adaptation name, not the name of the British series itself.
This distinction prevents a common mix-up between a programme's title and its format family. Dragons' Den began in Britain in 2005, while Shark Tank is the American adaptation. Other countries have used further local titles, but the British and American names are the most internationally familiar examples.