Montres Corum Sàrl, or Corum, is a Swiss watchmaker based in La-Chaux-de-Fonds, Switzerland founded by Gaston Ries and his nephew, René Bannwart in 1955. Corum's early success came when they introduced a watch made out of a $20 gold coin, which was an instant best-seller. The brand produces high-quality and high-price watches and is famous for its "World Premiers" line, which they produce in limited edition pieces each year. Their benchmark range is the "Admiral's Cup" series. In April 2013, Corum announced that it had been purchased by the China Haidian Holdings Limited group, today called Citychamp Watch & Jewellery Group under the leadership of Jérôme Biard, who was appointed on 1 September 2017.