Morgan Stanley's deputy head of investment banking, Ji-Yeun Lee, has left the firm in recent weeks, the Wall Street Journal reported, citing people familiar with the company.

Lee was a key lieutenant to Paul Taubman, who previously co-headed the company's investment bank. Taubman stepped down late last year and his long-time rival Colm Kelleher took full control of the unit.

Lee declined to comment to the Journal on her future plans. (http://link.reuters.com/vum97t)

The newspaper also said Morgan Stanley has re-hired John Collins, a mergers and acquisitions banker, from Moelis & Co, appointing him to a newly created role of global operations officer for the investment banking business.

Morgan Stanley could not immediately be reached for comment by Reuters outside of regular U.S. business hours.

(Reporting by Sakthi Prasad in Bangalore; Editing by Edwina Gibbs)