Continental led the group of 25 suppliers tracked by PricewaterhouseCoopers by providing its shareholders a 27.7 percent return in value in the first quarter.
The German-based partsmaker is benefiting from increased demand for its safety technology -- especially its electronic stability program.
Continental's automotive systems division sold more than 4.3 million ESP units in 2004, nearly 39 percent more than the previous year.
Many analysts rated the company as a buy after it reported its 2004 operating profit rose 28.2 percent compared with 2003 to E1.1 billion on sales of E12.6 billion.
The company expects another record profit in 2005.
German wiring systems specialist Leoni had a 27.16 percent gain in value in the first three months.
Its 2004 operating profit rose 50 percent compared with last year to E33.2 million on sales of E1.25 billion. It was helped by contracts to supply new or new-generations of high-volume models such as the Opel/Vauxhall Astra, BMW 1- and 3-series models and the Mercedes-Benz A class.
To fulfill these contract Leoni built new manufacturing facilities in the Ukraine, Romania and Slovakia.