Rival carmakers PSA Group and Fiat Chrysler Automobiles unveiled a plan to combine, pooling resources to confront an expensive new era of trade tariffs, emissions rules and electrification. Shareholders of each company will own 50% of the combined entity, to be listed in Paris, Milan and New York. Investors in Fiat will receive a dividend of 5.5 billion euros ($6.1 billion) and its robotics arm Comau, while France’s PSA plans to distribute its 46% stake in auto-parts maker Faurecia SE. Cost savings from the deal without plant closures are projected to be about 3.7 billion euros. PSA shares dropped as much as 9.1% in Paris, the most in more than three years, while Fiat rose as much as 10% in Milan. The boards of Fiat Chrysler and Peugeot and Citroen-maker PSA agreed to work toward a binding agreement in the coming weeks, they said Thursday in a joint statement. The accord would create the fourth-largest automaker with a combined market value of about $50 billion. A merger of Fiat Chrysler and PSA, the No. 2 for car sales in Europe, would create a regional powerhouse to challenge Volkswagen AG. The tie-up would bring together the billionaire Agnelli clan in Italy and the Peugeot ...