L'AQUILA, Italy (Reuters) - The process of selling Chrysler shares on the New York Stock exchange should shed light on the U.S. carmaker's value, Fiat FIA.MI and Chrysler Chief Executive Sergio Marchionne said on Thursday as he tries to seal a deal for the group.

A Fiat logo is seen on the wheel of a Fiat car in Turin in this picture taken February 10, 2013. REUTERS/Stefano Rellandini

Fiat, with 58.5 percent of Chrysler, wants to own it all. It has not been able to agree a price with the United Auto Workers union, which owns the rest via its retirees’ healthcare trust.

Chrysler last week filed papers for a flotation of the union shares. Though the offering could complicate Fiat-Chrysler ties, Marchionne saw a use from it.

“One of the things I hope is that it will become very clear exactly what the markets think Chrysler is worth, which is the only real reference point,” Marchionne said to journalists.

“There’s a pretty clear process that leads to the IPO, and it places clear road markers that can be recognized by both sides.”

A disagreement over the value of Chrysler has meant the owner of the stake, the union-affiliated healthcare trust VEBA, has not accepted Fiat’s offer.

Chrysler’s IPO filing last week warned the IPO could force Fiat to re-consider its alliance, causing commentators to note the reluctance from Fiat towards the offering made it unusual.

Marchionne currently runs the two companies as one, sharing technology, dealer networks, purchasing and management know how. Fiat wants to share Chrysler’s cash as well.

The Chrysler buyout talks are being closely watched by debt and equity investors, because Fiat’s long-term plan to cut losses in Europe depends on its ability to easily and cheaply share technology, cash and dealer networks with Chrysler.

“The alternative scenario of a Chrysler IPO could lead to a downgrade as it could complicate overall group corporate governance and management, in particular because of a fragmented shareholding structure, and lengthen the refinancing process of Chrysler’s debt,” said Fitch Ratings in a note on Thursday.

Fiat’s talks to buy up the remaining stake in Chrysler are continuing but have not made any progress, Marchionne added.

“The talks must continue,” he told reporters.

It is not clear how far apart the two sides are on price.