Shark finning increased since 1997 largely due to the increasing demand for shark fins. It is used in shark fin soup and traditional cures, particularly in China and its territories. The International Union for Conservation of Nature's Shark Specialist Group say that shark fin trade is causing a serious danger to the shark population. It estimates of the global value of the shark fin trade range from US$540 million to US$1.2 billion (2007). Shark fins are among the most expensive seafood products, commonly sold at US$400 per kg. In the United States, where finning is not allowed, some buyers regard the whale shark and the basking shark as trophy species, and pay $10,000 to $20,000 for a fin.