Much of the way influential consulting firm McKinsey & Co. operates is shrouded in secrecy. But recent reporting by the New York Times has revealed some of the company’s secrets, including its involvement with controversial companies like Purdue Pharma, the maker of OxyContin, as well as foreign leaders and governments in Saudi Arabia and South Africa. Additional stories have focused on the firm’s hedge fund MIO and alleged failures to make required financial disclosures. McKinsey has defended its work around the world. In a statement, the firm told the Times that “since 1926, McKinsey has sought to make a positive difference to the businesses and communities in which our people live and work.”  This week on Money Talking, Charlie Herman talks with New York Times investigative editor Walt Bogdanich and investigative reporter Mike Forsythe about their reporting on the often hidden world of McKinsey and why it matters.