Aldi is the common brand of two German discount supermarket chains with over 10,000 stores in 20 countries, and an estimated combined turnover of more than €50 billion. Based in Germany, the chain was founded by brothers Karl and Theo Albrecht in 1946 when they took over their mother's store in Essen, which had been in operation since 1913. The business was split into two separate groups in 1960, that later became Aldi Nord, headquartered in Essen, and Aldi Süd, headquartered in Mülheim. In 1962, they introduced the name Aldi, which is pronounced. In Germany, Aldi Nord and Aldi Süd have been financially and legally separate since 1966, although both divisions' names may appear with certain store brands or when negotiating with contractor companies. The formal business name is Aldi Einkauf GmbH & Compagnie, oHG.