SunLife has appointed Medialab to handle its estimated £30m media planning and buying account.
All Response Media has previously been the long-standing media agency on the UK business.
SunLife specialises in offering financial services including life insurance, equity release and funeral plans to the over-50s.
The brand has turned to Medialab "to create a data and insight planning partnership across offline and digital marketing investment and campaign attribution in order to deliver transformative outcomes in a highly competitive sector", according to a statement from the two companies.
Ian Cooper, head of distribution at SunLife, said: "We’ve been impressed by Medialab’s data capability, coupled with a hugely talented and passionate team, and look forward to working together to achieve SunLife’s ambitious goals."
Marcus Orme, founder and chief executive of Medialab, said: "It is an honour to be selected by SunLife as their partner for growth at such an important moment for their business. Our organisations are aligned in the ambition of creating insight from data to gain and grow valuable customers for SunLife and we are excited about the collaborative journey that lies ahead."
Orme founded Medialab in 2005 and describes the company not as an agency but as a "data marketing partnership that consistently delivers transformative outcomes for organisations we believe in".
Stewart Easterbrook, a former UK chief executive of Starcom Mediavest Group, is chairman of Medialab.
SunLife, which was founded in 1810 in London and Bristol, spends £30m a year on media in the UK, according to an estimate by Nielsen.