Aviva chief financial officer Pat Regan will leave the company in June to join Australian insurer QBE.
Regan, who joined Aviva in February 2010, has played a key role in the UK insurer’s £400m global cost-cutting drive over the past 18 months.
Aviva says it has already begun the search for Regan’s replacement and an announcement will be made “in due course”.
Aviva chief executive Mark Wilson says: “After a successful career at Aviva, Pat has decided to take a new role outside the group.
“Pat has been a tremendous support in assisting me with Aviva’s financial transformation. I am supportive of his decision, and he leaves with my best wishes and those of Aviva’s board.”
Regan adds: “Whilst I am excited about my new role at QBE, I am also sad to be leaving Aviva.
“Aviva is a great business with a bright future ahead of it. I have thoroughly enjoyed working with Mark and I wish him and everyone who works for Aviva all the best for the future.”