The Stagwell Group, a private equity firm that manages investments in new media and digital marketing services, invested $100m in MDC Partners, an advertising and marketing holding company based in New York City. In connection with the transaction, industry veteran Mark Penn will join MDC Partners as Chief Executive Officer and a member of its Board of Directors. Presiding Director of the MDC Partners Board of Directors, Irwin Simon, commented: "After a thorough review process, consultation with our advisors and careful consideration of our objectives, we are delighted to welcome both Mark as CEO of MDC Partners, and The Stagwell Group as a long-term strategic investor. Throughout his career, Mark has proven himself a powerful strategic operator and passionate supporter of agencies. He shares our vision and our values, and his background as a marketer, agency founder, global thought leader and investor will be critical to bolstering our structure, solutions and services."