The event was won by South Korea's Park In-bee, who raced past her challengers with a final-round six-under 65 to win by three shots.
Park, the second-ranked player in the world entering the tournament, earned her second victory of the season to join compatriot Kim Sei-young and Ko with multiple LPGA victories this season.
Ko said before the event that all her winnings would go towards the relief effort in quake-hit Nepal. After a poor first round it looked like the 18-year-old wouldn't be earning any money from the tournament before she bounced back to make the cut.
Ko, coming off a win last week in California, will also maintain the No. 1 ranking after a closing 71 to finish at even par.
South Korea's Park Hee-young and American Cristie Kerr shot matching 66s to finish tied for second while American Lexi Thompson finished at 11-under alongside Sweden's Maria McBride.
The 18-year-old said before the event that all her winnings would go towards the relief effort in quake-hit Nepal. After a poor first round it looked like Ko wouldn't be earning any money from the tournament before she bounced back to make the cut.
A week after earning NZ$398,000 the week before, Ko walked away with just $8285 today.
"I didn't know if I was even going to be able to make the cut or even make a donation," said Ko, who was just on the line to make the primary cut Saturday and secondary cut Sunday.
"Luckily, I was able to play all four days. ... The last three days was a lot of grinding, but I'm happy that I can contribute."
- additional reporting NZ Herald