AUBURN HILLS – Fiat and Chrysler paid $4.35 billion to buy 41.5 percent of Chrysler?s shares that had been owned by the UAW Retiree Benefits Trust, shoring up the trust, which provides medical benefits to 117,000 UAW-represented Chrysler retirees and their dependents.

The combined companies comprise the seventh largest global automaker in the world. But what it will be called, and on what stock exchange it will be listed, remains to be seen.

Chrysler, which has been sold three times since 1998, hasn?t been publicly listed since then. Fiat is listed on the Milan Stock Exchange, where it?s stock closed at 7.45 Euros Wednesday, a two-year high.

Fiat CEO Sergio Marchionne?s last week at the North American International Auto Show said it was his preference for the stock of the combined company to be traded on a U.S. stock exchange and for the company to be legally incorporated in the United States.

These issues will be decided next week by the Fiat board of directors. One major issue they won?t have to worry about is a lawsuit by the UAW trust over Chrysler shares and will drop its demand for Chrysler to go public with the shares owned by the trust. Under terms of the agreement, that lawsuit has been dropped.