Serta is a company that specializes in making mattresses. It was founed in 1931 by 13 mattress manufacturers who licensed the Serta name, and now eight independent licensees acting like a cooperative own the company. Its largest licensee National Bedding Company (which owns 19 of 26 Serta factories) manages Serta. It is famous for its "Counting Sheep" advertising campaign which were animated by Aardman Animations. It is the second largest mattress brand in the United States. Serta Mattresses are also offered on cable home shopping channel ShopNBC