Ian Thompson takes over as the new Chief Credit Officer at S&P. He replaces Mark Adelson, who will remain as a senior fellow at S&P. He was hired by the previous CEO, Deven Sharma. Deven Sarma was replaced by former Citigroup excutive, Doug Peterson, in September 2011, weeks after the downgrading of the U.S. sovereign credit rating. Ian Thompson reported to Mr. Adelson, as the head of the Asia-Pacific region. Adelson joined in 2008 with the task of making it difficult to earn the highest credit rating for issuers following the subprime mortgage crisis, in which credit rating firms gave top ratings to lower quality mortgage securities. Mr. Jacob, the structured finance chief, will also be leaving S&P. The frequent management changes are viewed as making it harder for S&P to win back credibility in its ratings.