The head of ratings at Standard & Poor's, Vickie Tillman, has moved to another role at the ratings firm's parent McGraw-Hill, according to people familiar with the matter.

Tillman, who has worked at S&P for more than 30 years, was an executive vice president at the company's ratings group and was its highest-ranking executive over the last decade. She will take up a newly created position overseeing "sustainability" at McGraw Hill, the company's chief executive Terry McGraw told employees in a memo on Tuesday.