Chrysler Group LLC says Fiat has increased its ownership stake in the company after hitting its first performance-related milestone.

Fiat now owns 25 percent of Chrysler — up from 20 percent — making it the company's second-largest owner. UAW VEBA has a 63.5 percent stake in Chrysler.

Fiat's ownership interest increased automatically under terms of a deal tied to commercial production of the fully integrated robotized engine. The engine will be in the new Fiat 500.

Chrysler said Monday that Fiat can boost its stake to 35 percent, in 5 percent increments, if it meets two other milestones.

Last week Fiat CEO Sergio Marchionne said it's possible Fiat will increase its stake in Chrysler to more than 50 percent this year.