Switch-ups at the head of car companies is something the American public has grown accustomed to, as the past year has seen a lot of heads roll. But Italians will no doubt be looking for a more complete explanation for the sudden resignation of Luca di Montezemolo as chairman of Fiat, announced at a press conference in Turin today.

Montezemolo will stay on as chairman of Ferrari and on the Fiat Board of Directors. He says that he has completed the task assigned him by the "core shareholder" in May 2004--but provides no other reason for stepping down. Current vice chairman John Elkann will take his place.

Sergio Marchionne is expected to remain as Fiat's CEO. Marchionne is also the post-acquisition CEO of Chrysler, leading him to work seven days a week most weeks, with frequent trips back and forth between Italy and the U.S. It's not yet clear what, if any, impact the changeup at the top of Fiat's structure will have on Chrysler or Fiat's U.S. plans and operations.

We'll keep you up to date as the story unfolds, with a special eye to what this might mean for Chrysler, the U.S.-bound Fiat 500, or other products that may--or may not--be headed our way.

[Fiat]