Standard & Poor's President Deven Sharma is relinquishing his post less than a month after the ratings agency issued its monumental downgrade of the United States. Sharma will stay on as an adviser working on the company's strategic portfolio review until the end of the year, S&P parent company The McGraw-Hill Cos. (MHP) said in a press release Tuesday. Douglas Peterson will replace Sharma, effective Sept. 12. Peterson is chief operating officer at Citigroup's (C) Citibank unit. Sharma's departure isn't related to the historic and unprecedented downgrade of the U.S. credit rating nor the ongoing Justice Department investigation into the firm, according to the Financial Times, which broke the news earlier Tuesday. Sharma joined Standard & Poor's in 2006 as executive vice president of investment services and global sales. He was named president in 2007. Sharma first joined McGraw-Hill in 2002. McGraw-Hill Chairman, President and CEO Harold McGraw III said "S&P is a stronger company," after Sharma's four years at the helm. "As was announced at the end of last year, Standard & Poor's was split into two separate organizations — S&P, our credit ratings service, and McGraw-Hill Financial — to enable both organizations to serve investors and customers more effectively," McGraw said. "Deven assisted us with the creation of these two high-growth segments and was then ready for new challenges. Accordingly, we began a process to identify a new leader for S&P." Write to Jason Philyaw. Follow him on Twitter: @jrphilyaw