The American wrapped up the title after victory in the penultimate women's World Cup slalom on Saturday.
Feuz now leads Svindal by 60 points with one race remaining, the FIS Alpine Ski World Cup Final in Åre in Sweden.
After becoming just the fourth American to win multiple overall titles with a third-place giant slalom finish on Friday, Shiffrin now stands all alone in second with the most women's technical event (GS, slalom) wins at 37.
Shiffrin won slalom gold at the 2014 Sochi Olympics at the age of 18, a year after she won the first of her three consecutive world slalom titles.
Reflecting on her 42nd career World Cup win and her sixth in the slalom this season she added: "I knew Wendy had had a good second run but I said 'No Wendy, not today!'" Holdener failed to win or finish in second place, which was the only mathematical chance Shiffrin could be knocked out of contention.More news: Waymo launching self-driving truck pilot in Atlanta
And she did it with five races left in the season.
The season-ending World Cup finals are next week in Are, Sweden.
Also, getting her 11th win of the season was a personal best, though Schneider (14 in 1988-89) and American teammate Lindsey Vonn (12 in 2011-12) won more races in a single season.
The race was won by Ragnhild Mowinckel of Norway. "Hopefully, I'm not going to be feeling a lot of nerves (in Are) because there is not a lot of risk".
Mikaela Shiffrin of United States of America takes 3rd place during the Audi FIS Alpine Ski World Cup Women's Giant Slalom on March 9, 2018 in Ofterschwang, Germany.