Ken Griffin's Citadel has joined the growing list of hedge funds and another investment firms tapping Morgan Stanley for new recruits with the appointment of Li Sun as a quantitative researcher focused on global credit.

Sun, a PhD physicist, spent almost nine years at Morgan Stanley, according to his LinkedIn profile. He first joined the business as an associate in the firm's Beijing office in May 2014 before making a move to New York later that year and working his way up to vice president and finally executive director, apposition he held for over four years before agreeing to join Citadel.

Sun is the second former bank exec to join Citadel in the last month or so following the appointment of Goldman Sachs MD Francis Giannaros as the $62.3 billion firm's head of research and modelling engineering in equities last month.