The business, which will be based at M&C Saatchi's Golden Square headquarters, is the brainchild of the founders Jane Hodson and Rhian Woods, and will be called M&C Saatchi Milk. Hodson and Woods both take on the role of joint chief executive.
Milk's activity will be rooted in data and it will work closely with M&C Saatchi's central strategy unit. The business will focus on providing data, insight and strategy, as well as data analysis.
The pair teamed up at OgilvyOne, where Hodson had spent 13 years, heading its strategic services team of 40. Woods was a board director, in charge of the strategic data and analytics offering.
M&C Saatchi's investment in Milk follows its recent acquisition of the social media agency Human Digital.
Lisa Thomas, the chief executive of M&C Saatchi UK Group, said: "We can't underestimate the importance and power of data in today's marketing mix, and it's essential that we give clients an intelligent and practical approach to sifting out the real business drivers."