Maserati North America Inc. announces the departure of CEO James Selwa, effective today, and says a search for his replacement has begun.

Roberto Ronchi, CEO of parent company Maserati SpA in Modena, Italy, will assume responsibility for the unit with assistance from members of the North America team.

“We greatly appreciate the hard work of Jim and his team during a very challenging period,” Ronchi says in a statement.

Selwa is leaving Maserati to pursue other opportunities. During his three years with Maserati North America, the unit doubled its sales and increased its distribution network 18%. It also received significant investment during that period from owner Fiat SpA, which bought the company in 2005.

Last year, Maserati North America sales rose 33% vs. 2006, an increase the importer credits mostly to the introduction of a 6-speed automatic transmission on its flagship Quattroporte sedan.

The North American market favors an automatic transmission, company executives told Ward’s at the Detroit auto show last month. North America ranks as Maserati second most important market behind Italy.