Fiat Chrysler Automobiles and PSA Group completed their US$52 billion tie-up and formally merged into Stellantis.

The merger will create an auto group with combined annual sales of around 8.1 million vehicles and deep enough pockets to fund the shift to electric driving and take on bigger rivals Toyota and Volkswagen Group.

"The merger between Peugeot S.A. and Fiat Chrysler Automobiles N.V. that will lead the path to the creation of Stellantis N.V. became effective today," the two automakers said in a statement.

It took over a year for the Italian-American and French automakers to finalise the deal, during which the global economy was upended by the COVID-19 pandemic. They first announced plans to merge in October 2019.

Shares in Stellantis will start trading in Milan, Paris, and in New York this week. PSA CEO Carlos Tavares will hold his first press conference as Stellantis CEO on Wednesday (NZ time),

Analysts and investors are turning their focus to how Tavares plans to address the huge challenges facing the group – from excess production capacity to a woeful performance in China, says Europe Automotive News.

FCA and PSA have said Stellantis can cut annual costs by over 5 billion euros ($6.1 billion) without plant closures, and investors will be keen for more details on how it will do this.

FCA produces Abarth, Alfa Romeo, Chrysler, Dodge, Fiat, Jeep, Lanica, Maserati and Ram, while PSA has Peugeot, Citroen, DS, Vauxall and Opel in its stables.