[3][4] He joined the United States Department of the Treasury in 2005 as a financial economist and became Director of the Office of Debt Management in October 2006.
[1] On September 25, 2008, Ramanathan was designated Acting Assistant Secretary of the Treasury for Financial Markets by President George W. Bush.
[3][5][6] In April 2010, Ramanathan was hired by Fidelity Investments to become senior vice president and director of Bonds at the mutual fund company.
[8] As of 2024, Ramanathan joined Payden & Rygel as a Senior Vice President at the Boston office within client servicing.
Ramanathan is a 2010 finalist of the Samuel J. Heyman Service to America Medals, for having "orchestrated the sale of Treasury bills that raised $1.7 trillion in the midst of a severe global economic crisis, helping stabilize the U.S. financial system and fund the country's massive budget deficit and national debt," according to the citation.