The insurer is reviewing all digital media planning and buying as well as its search strategies across brands and products including esure, First Alternative, Halifax Car Insurance and the female- focused car insurance brand Shelias' Wheels. The review also covers affiliate partnerships and display activity.
Carat, the incumbent on the offline account, is unaffected by the review.
Dorothy Fulton, who was appointed as the head of marketing at esure in May, will lead the process.
Esure appointed Equimedia in 2008, after a pitch against undisclosed agencies.
The review does not affect the company's arrangement with its digital agency, The Unit, which creates banners and marketing activity using online platforms such as Facebook. Esure's above the line creative is handled in-house.
Over the past ten years, esure's advertising has become known for featuring the film director-turned-food-critic Michael Winner, who used the catchphrase "calm down, dear".