Futcher and Shin both finished with six birdies and one bogey to reach 8-under 136 along with first-round leader Angela Stanford, who had a 70 on Friday.
Shin brushed off her lone bogey on 13 to score three straight birdies and vault into contention.
“My putting has been great the last two days so I’m happy to be where I’m at,” said 19-year-old Shin, who moved to the Los Angeles area as a child. “That’s really helped me with my confidence.”
No. 1-ranked Yani Tseng shot a 72 to remain 1 under and seven strokes off the lead, with bogeys on the 13th and 18th holes undermining her bid to climb the leaderboard. Tseng is seeking her second win of the year after her victory at last week’s LPGA Thailand, but has never won in Singapore.
“It was bad,” Tseng said. “I feel I hit the ball pretty good, but my score was terrible and I don’t know why. I didn’t make putts and I didn’t have much birdie chances actually.”
Futcher got off to a quick start with four birdies on the front nine.
“I’ve just been hitting the ball really solidly, hitting greens and giving myself a lot of chances,” she said.
Like the cartoon character Popeye with his spinach, Futcher said eating up to 10 strips of bacon during a round helps her play better.
“I will definitely have to find some bacon for this weekend,” the 29-year-old Penn State graduate said.
The 63-player field includes 18 of the top 20 in world rankings.