Sigurd Reinton was until 2013 a director of NATS Holdings, which provides the air traffic control services for UK and North Atlantic airspace, and for the main UK airports. At NATS, he served on the Audit and Nominations Committees and chaired the Stakeholder Council.
He was Chairman of the London Ambulance Service NHS Trust for ten years until 2009 and before that of Mayday University Hospitals NHS Trust. He was a member of the Board of the Ambulance Services Network and of the advisory board of The Foundation. He was a member of the Council of the NHS Confederation from 1998 to 2007 and was the lead for London. He was previously a Director (senior partner) at McKinsey & Company.