Guillermo Ulacia Arnaiz serves as Vice President of Aceralia Corporation Siderurgica SA.
[1] Arnaiz served as the chief executive officer of Gamesa Corporación Tecnológica from December 1, 2005.
He has previously served as Vice Chairman of General Motors Corp, Spanish unit; he also served as Executive Chairman since July 2006 until October 2009.
[citation needed] Arnaiz worked for 10 years as a Director of flat steel products at Arcelor before becoming Vice President.
[citation needed] Arnaiz serves as Co-Chairman of the Aceralia Management Committee, member of the General Management of the Arbed Group.