Alten is a holding company. Through its subsidiaries, Co. operates in three areas: Engineering and Technology Consulting (ETC), Telecoms Networks and Multimedia, and Information Systems (NTIS). Through the Engineering and Technology Consulting (ETC) segment, Co. studies and designs technology products for technical divisions in industry and telecoms. The Telecoms Networks and Multimedia segment focuses on Product design, Architecture, deployment, and operation of networks. Lastly, the IT systems segment comprises Applications and software development, and Infrastructure and Telecoms (Applications, systems and networks Corporate telecommunications).

APERAM is a stainless and specialty steel producer. Co. produces a range of stainless steel products and products including electrical steel (grain oriented, non-grain oriented, and non-grain oriented semi-processed steel), nickel alloys and specialties. Co. sells its products to customers on three continents in over 40 countries, including aerospace, automotive, catering, construction, household appliances and electrical engineering, industrial processes, medical, and oil & gas industries. Co. manages its business according to three operating segments: Stainless and Electrical Steel; Services and Solutions; and Alloys and Specialties.

Grenkeleasing is engaged in providing financial services in three business segments: Leasing, Banking and Factoring. Leasing: Co.'s financing activities are focused on small-ticket IT leasing. Co. finances a wide range of goods, primarily in the area of information technology on IT equipment and systems and software. Banking: Through GRenke Bank AG, Co. provides financing products for small and medium sized enterprises focused on German customers, including lower-volume receivables (factoring) and car leasing. Co. also offers payment transactions and investment products. Factoring: Co. performs traditional factoring services in Germany and is a financial service provider. .

Groupe IDI activity is divided in two areas: through its subsidiaries, EURIDI and Marco Polo Investissements, Co. is engaged in management buy-out/buy-in and growth capital investments in French small-mid caps valued between Euro7,000,000 and Euro75,000,000 also, through its subsidiary, IDI Mezzanine, is engaged in mezzanine financing. Also Co. is active in the purchase of secondary market portfolio.

SFC Energy provides fuel cell generators for off-grid power applications, low and medium voltage electrical machine power products, instrumentation and measurement solutions, gas and flame detection safety systems as well as supervisory control and data acquisition solutions. For the power electronic market, Co. provides high-power electronic components, external and internal converters, switch mode power supplies, and special coils. For the defence and secutiry market, Co. provides portable power solutions that soldiers can use to run the devices they carry while on dismantled deployment. For the consumer market, Co. provides fuel cells used in hybrid operationalong with a solar module.