Since joining Orascom, the family business in 1979, Sawiris has contributed to the growth and diversification of the company into what it is today one of Egypt's largest and most diversified conglomerates and the country's largest private sector employer. Sawiris built the railway, information technology, and telecommunications sectors of Orascom. Management decided to split Orascom into separate operating companies in the late 90s: Orascom Telecom Holding (OTH), Orascom Construction Industries (OCI), Orascom Hotels & Development and Orascom Technology Systems (OTS).