In 1996, he was promoted to Worldwide Head of Debt Capital Markets Services. In 2001, Chammah's responsibilities were extended to include Worldwide Leveraged Finance and in 2002, he formed and was Head of the Global Capital Markets Group, which combined the Firm's debt and equity capital markets activities. In 2005, Chammah was named Global Head of Investment Banking and in September 2007 he was named Co-President of the firm, a position he held until December 2009.