By Mike Stone and Olivia Oran

(Reuters) - Morgan Stanley (>> Morgan Stanley) named John Collins as the co-head of its global healthcare banking group, according to an internal memo on Wednesday. He replaces Clint Gartin, who will become chairman of investment banking.

A veteran mergers and acquisitions banker, Collins most recently served as global operations officer in the investment banking division.

Collins started his career at Morgan Stanley in 1990 as an analyst and was promoted to managing director in 2004. He left to join Moelis & Co (>> Moelis & Co) in 2010 before rejoining Morgan Stanley in 2013.

Collins will work alongside healthcare banking co-head Michele Colocci and will focus on building out the firm's global client base. He will start at his new role in January.

Gartin joined Morgan Stanley in 1981 and became a managing director in 1991. He has held a number of roles within the firm, including chief administrative officer of investment banking and most recently, vice chairman of investment banking and global co-head of healthcare.

A Morgan Stanley spokeswoman confirmed the contents of the memo.

Morgan Stanley ranks No. 2, both in the United States and globally, in the M&A advisory league tables. The healthcare group has advised on high profile deals recently including Pfizer Inc's (>> Pfizer Inc.) $160 billion deal for Allergan PLC (>> Allergan, Inc.) and Shire PLC's (>> Shire PLC) and Perrigo Company PLC's (>> Perrigo Company PLC) successful defense against a $31 billion hostile takeover attempt by Mylan NV (>> Mylan NV).

(Reporting by Mike Stone and Olivia Oran in New York; Editing by Frances Kerry)