Defending champion Suzann Pettersen of Norway carded a 69 to move into a tie for third with South Korea's Ju Young Pak and Amy Yang, who both shot 71.
"I expected to be in contention the way I've been playing, that's all I can ask for," said Pettersen, who is second on the money list. "We'll see where I go out tomorrow, but I feel pretty comfortable with the position I'm in."
Alison Walshe of the United States had seven birdies against three bogeys for a 68 to finish in a four-way tie for sixth.
South Korean star Inbee Park, who leads the money list and the player of the year rankings, struggled with her game and finished with a 73 that left her tied for 22nd with three others, including Na Yeon Choi of South Korea, who won here in 2009 and 2010.
Michelle Wie, who started the second round just two strokes off the lead, is tied for 15th after a 73.
Since the tournament's first year in 2002, a South Korean has taken home the title seven times.
