The rest of the new Ferrari shares will be distributed to group shareholders.
"I am delighted to have taken this additional step in the development of FCA," chairman John Elkann was quoted as saying in a company statement.
"Coupled with the recent listing of FCA shares on the NYSE, the separation of Ferrari will preserve the cherished Italian heritage and unique position of the Ferrari business," he said.
The spin-off will be completed next year, and the company said it expected shares to be listed in the United States as well as possibly a European exchange.
Fiat head Sergio Marchionne said pursuing "separate paths for FCA and Ferrari" was the "best course of action to support the long term success of the Group while at the same time substantially strengthening FCA's capital base."
The Italian group also released its third-quarter results, reporting a 7.4 percent increase in profit thanks largely to growth in US sales.
Earnings before interest and taxes were €926 million ($1.18 billion), up from €862 million a year earlier, it said.