FILE PHOTO: The Goldman Sachs company logo at the New York Stock Exchange, April 17, 2018. REUTERS/Brendan McDermid/File Photo

NEW YORK (Reuters) - Goldman Sachs Group Inc GS.N has appointed investment bankers David Dubner and Pete Michelsen to be co-heads of activism and shareholder advisory for the Americas, the bank said on Monday in a memo.

The new roles come at a time when public companies have been seeking help to better defend themselves against so-called activist investors, who often demand corporate changes ranging from sale processes to share buybacks.

Dubner is a managing director in the M&A group and joined the bank in 2006. Michelsen is a managing director in M&A as well, having originally joined Goldman Sachs in 2005. Michelsen's LinkedIn profile shows he left the bank in 2014 to work at CamberView Partners, LLC, a shareholder advisory firm that was acquired earlier this year by PJT Partners Inc PJT.N.

Steven Barg will stay on as global head of activism and shareholder advisory while Nimesh Khiroya will continue to lead the bank’s efforts in Europe, the Middle East and Africa, the memo said.