Shark Tank was the title of the United States adaptation of the format behind Britain's Dragon's Den.
Both programmes present entrepreneurs to a panel of wealthy investors, who question the pitches and may offer money for an ownership stake. The British version kept the “dragon” metaphor, while the US version used “sharks” to describe its investors.
Shark Tank premiered in the United States in 2009 on ABC. Its panel has included investors such as Mark Cuban, Barbara Corcoran, Kevin O'Leary, Daymond John and Lori Greiner, although the lineup varies by episode and season.
The two programmes are related adaptations rather than the same production. Dragon's Den itself was adapted in Britain from the Japanese format Money Tigers. This chain of adaptations is why different countries use different titles and investor metaphors for a similar pitch structure.