Since 1990, Nassef Sawiris takes charge the supervision of the construction activities of Orascom, and in 1998, he became the Chief Executive Officer of the Orascom Construction Industries which was founded by his father Onsi. The company is considered as the most valuable publicly-traded company in Egypt. Nassef Sawiris has an estimated net worth of $5.67 billion as of April 2017, according to Bloomberg.

In 2011, it was announced that the company has plans of splitting the fertilizer and construction into 2 publicly traded companies during the first quarter of 2012. In October 2011, Nassef Sawiris made an investment to the EBX Group which is owned by the Brazilian billionaire Eike Batista. The partnership aims to develop nitrogen fertilizer plants in Brazil.

He was part of the Board members of the NASDAQ Dubai, Besix (Belgium) and NNS Holding (Luxembourg). He also served as the president of Egyptian Cement Company and director of Lafarge.

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