Choi, seeking her second win of the season, finished at 12-under-par 204 -- one better than second-round leader Ai Miyazato, who lost ground with a double-bogey on No. 2 and went on to record a 71.
Miyazato ended with sole possession of second place at minus-11, while first-round co-leader So Yeon Ryu (68) finished Round 3 two shots back at 10-under.
The Group Titleholders event is comprised of the Top 3 finishers in each official LPGA Tour event.
Notable deaths of 2014 [PHOTOS]