Citadel is trimming its investment division following the firm's losses in the early part of 2016.
CNBC has confirmed that Citadel has cut more than a dozen employees from Surveyor Capital, one of the firm's divisions, as The Wall Street Journal first reported.
A person familiar with the situation confirmed to CNBC that Citadel's flagship Kensington Wellington fund has fallen 6.5 percent year-to-date as of Feb. 12.
Surveyor Capital, a global equity division of Citadel, had roughly 200 employees before this report.
Hedge funds as a group had a tough 2015, posting their worst year since 2011, according to investment research firm Eurekahedge.