WESFARMERS has continued to streamline its retail-centric portfolio by offloading non-core assets after striking a $1.85 billion deal -- the biggest divestment in its history -- to sell its insurance underwriting business to Insurance Australia Group. Chief executive Richard Goyder said exiting the volatile insurance business -- which generated only 3 per cent of revenues last year and delivered average returns of just 6.6 per cent in the past five years -- would de-risk the Wesfarmers portfolio and represented a "win-win" for both Wesfarners and IAG.