The automaker is accused of misrepresenting the number of vehicles it sold monthly in the U.S. between 2012 and 2016.
According to regulators, the Detroit car company falsely promoted a streak of uninterrupted monthly year-over-year sales growth while in reality the growth streak was snapped in September 2013.
The SEC found that Fiat paid dealers to report fake vehicle sales while also maintaining a database of actual but unreported sales, which employees referred to as the "cookie jar."
"New vehicle sales figures provide investors insight into the demand for an automaker's products, a key factor in assessing the company's performance," said Antonia Chion, associate director in the SEC's Division of Enforcement. "This case underscores the need for companies to truthfully disclose their key performance indicators."
The latest news follows a report earlier this week that said a senior manager at the company was charged in connection with the Justice Department's probe into diesel emissions cheating.
Fiat Chrysler shares fell 0.4% to $12.93 on Friday.
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