Upward nominal wage rigidity / Paulo Guimarães (Banco de Portugal, CEFUP and IZA), Fernando Martins (Banco de Portugal, UECE and Universidade Lusíada de Lisboa), Pedro Portugal (Banco de Portugal, Universidade Nova de Lisboa and IZA) ; IZA, Institute of Labor Economics. Bonn, Germany : IZA Institute of Labor Economics, January 2017