Karl Albrecht of , a suburb of Essen. Theo completed an apprenticeship in his mother's store, while Karl worked in a delicatessen shop. Karl served in the Wehrmacht during World War II and was wounded on the Eastern Front. After the war, the brothers jointly took over their mother's business and founded Albrecht KG. They separated that company in 1961 into Aldi Nord, covering the part of Germany north of the Ruhr under Theo Albrecht, and Aldi Süd under Karl. The first Aldi (short for Albrecht Discount) was opened in 1962. In 1994, Karl Albrecht removed himself from the daily operations of
Perekrestok (supermarket chain) connected. In November 2017, X5 introduced machine learning to bolster targeted marketing at the Perekrestok supermarket chain, and developed personalised offers for all members of the Perekrestok Club loyalty program. The company leverages machine learning to group customers into segments based on common features and create offers for them. The system analyses groups of customers and designs personalised marketing campaigns based on demographic and several hundred behavioural factors, such as: frequency of purchases and ticket size, customer preferences, lifestyle fundamentals, acceptable price levels, favourite product categories and preferred shopping hours. Customer sensitivity to offers is predicted using various analytical models.