Paris-based Publicis is one of the world’s “Big Four” advertisting and public relations companies. The Epsilon purchase is the largest in the firm’s 93-year history. It’ll give Publicis access to more consumer data and help speed its shift from traditional TV and print ads to digital marketing services. Publicis owns agencies such as Saatchi & Saatchi, Leo Burnett and Publicis Media, and works with some of the biggest brands, including Toyota, Samsung, General Motors and Procter & Gamble. “Epsilon is a unique asset with world-class capabilities that many of Publicis Groupe’s clients are clamoring for us to add to our current portfolio,” said Publicis chairman and CEO Arthur Sadoun in a statement. As part of the agreement, Publicis said it will also work more closely with Alliance Data’s loyalty marketing and credit card divisions.