I believe the record is 613 years, by Stora Kopparbergs Bergslags AB, a Swedish mining company. It was founded in the 13th century as Stora Kopparberg (first r

I believe the record is 613 years, by Stora Kopparbergs Bergslags AB, a Swedish mining company. It was founded in the 13th century as Stora Kopparberg (first record is a private stock sale in 1288). It went public on the Stockholm Stock Exchange in 1901. Today it's known as Stora Enso Oyi, following a merger with the Finnish company Enso in 1998.