Which car stock has spiked the most in 2018?

U.S. automakers are driving into the New Year with renewed optimism, thanks in part to President Donald Trump’s tax reform bill that drastically cuts the corporate tax rate.

Car stocks are seeing gains since Jan. 2, the first trading day in 2018.

Fiat Chrysler (NYSE:FCAU) has made the biggest leap this year, up 31%, and recently committed to paying its workers bonuses in the wake of a U.S. tax cut.

“It was a morally owed thing to do at some point in time. I think tax reform made it unquestionably due now, and so it helped that thinking process,” Fiat Chrysler CEO Sergio Marchionne told FOX Business’ Jeff Flock at the Detroit auto show.

The Italian-American automaker said it will pay out a $2,000 bonus to about 60,000 U.S. workers, joining corporate giants such as Wal-Mart Stores (NYSE:WMT) and AT&T (NYSE:T).

With stocks hitting new all-time highs to kick off 2018, other automakers have followed suit.

Tesla (NASDAQ:TLS) is up 8%, followed by General Motors (NYSE:GM) at 7% and Ford (NYSE:F) with a 6% gain.