In the final round, Ko shot a four-under 68 and finished with a 10-under 278 in a tie with Julieta Granada of Paraguay and Carlota Ciganda and Spain.
Ko and Ryu So-yeon of South Korea started the final round three strokes behind the leader, Granada.
Ko was ranked third on LPGA Tour's official money list with season earnings amounting to US$2.08 million.
Earlier this month, the 17-year-old was named as winner of the 2014 LPGA Rookie of the Year award.
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