Gyllenhammar was board member of Polygram NV from 1996 and became chairman of the board of Commercial Union PLC in 1998 and senior advisor of Lazard Frères & Co LLC in New York City in 1996.
Gyllenhammar var styrelseledamot i Polygram NV från 1996, blev styrelseordförande Commercial Union PLC 1998 och senior advisor i Lazard Frères & Co LLC i New York 1996.