The fourth-largest group life insurer is trying to get the attention of more brokers, human resources executives and top-level corporate executives.

Minnesota Life , a unit of Minnesota Mutual Companies Inc., St. Paul, Minn., has signed Atomic Playpen Interactive + MJ Kretsinger Advertising, Minneapolis, to be its new advertising agency.

Atomic Playpen will start by strengthening Minnesota Life’s presence on the Web, according to Minnesota Life.