The paper said talks of the move have been circulating among investors and hedge-fund consultants over the past few days.
Walthour left Aksia, a New York-based investment-consulting firm, in December, according to the paper.
Citadel could not be immediately reached for comment by Reuters outside regular U.S. business hours.
Kenneth Griffin, long considered one of the industry's best managers, delivered gains of 62 percent to investors in Citadel's flagship Kensington and Wellington funds in 2009, an investor told Reuters in December.
(Reporting by Ajay Kamalakaran in Bangalore; Editing by Anshuman Daga)