Aldi is a leading global discount supermarket chain with almost 10,000 stores in 18 countries, and an estimated turnover of more than €50bn. Based in Germany, the chain was founded by brothers Karl and Theo Albrecht in 1946 when they took over their father's store in Essen which had been in operation since 1913; it is one of the world's largest privately owned companies. The brothers built up a chain of stores until, by 1960, they owned 300 shops, and split the operation into two separate groups, that later became Aldi Nord, headquartered in Essen; and Aldi Süd, headquartered in Mülheim an der Ruhr. The two operate independently, each within specific areas. In 1962 they introduced the name Aldi (a syllabic abbreviation for Albrecht Diskont), which is pronounced . In Germany Aldi Nord and Aldi Süd have been financially and legally separate since 1966, although both divisions' names may appear (as if they were a single enterprise) with certain store brands or when negotiating with contractor companies. The formal business name is Aldi Einkauf GmbH & Compagnie, oHG.