Westfield Health has submitted a planning application for the move of its UK Headquarters to a new site in its home city of Sheffield.
The insurer applied to Sheffield City Council for planning permission for Milton House, on Charter Row in the city, which it purchased last year.
Westfield Health has been based at Westfield House on Division Street in the City since 1975, the refurbishment of Milton House will continue until spring/early summer 2016.
When completed there will be a new reception area, reception for Westfield Health on the fifth floor and a new customer service function for policy holders.
Other planned alterations include an outdoor roof terrace and a new office atrium to connect Westfield's offices internally.
"Move champions" have been appointed across Westfield Health staff as part of the move.
Julie Gill, executive director - operations at Westfield Health, said: ""With our centenary approaching, our forthcoming move to Milton House signifies a new era for Westfield Health.
"This is a really exciting time for us - we have a bold, standout brand and we're continuing to grow as an organisation, now serving more than 400,000 policyholders across the UK - the highest number in our history.
She added: "Sheffield has been our home for almost 100 years, and our roots are firmly embedded here.
"Our move to Milton House reinforces our commitment to Sheffield, keeping our headquarters accessible for our customers and playing an integral part in the regeneration of the city centre."
