(Adds detail on changes at Citigroup)
SINGAPORE, Sept 17 (Reuters) - Citigroup's Southeast Asia head of financial institutions, David Khoo, has resigned less than two years after joining the U.S. bank, a banking source with direct knowledge of the matter said on Monday.
Khoo, who has also worked for RBS and ABN AMRO, joined the firm in early 2011.
A Citigroup spokesman declined to comment, and an email to Khoo was returned with a message that his email address no longer exists within Citigroup.
His departure comes after high-profile changes at Citigroup's Southeast Asia business, concentrating on capital markets, and mergers and acquisitions.
In July, Citigroup poached Will McLane from Morgan Stanley and named him head of corporate and investment banking for the ASEAN region and head of the financial institutions group in the Asia-Pacific region.
McLane, who worked for Morgan Stanley for 15 years, has been involved in some of the region's biggest deals in the financial sector.
Southeast Asia has been a hot spot for dealmaking this year.
Citigroup is advising Indonesia's Bank Danamon, the subject of a $7.3 billion takeover bid from DBS Group in Singapore. The deal is awaiting regulatory clearance.
Citi was sole financial adviser to San Miguel Corp for the sale of its 60 percent stake in Bank of Commerce to Malaysia's second-biggest bank CIMB Group. (Reporting by Saeed Azhar; Editing by Daniel Magnowski)