Aging products
Meanwhile, budget rivals such as Dacia and Kia posted gains in Europe during the first four months. Dacia's volume rose 18 percent to 90,162 while Kia's sales were up 4 percent to 112,795, equivalent to a 2.2 percent and 2.7 percent share, respectively.
Analysts say an aging product lineup and lack of focus on Europe have hit Chevrolet's vehicle sales.
Most of the brand's cars sold in Europe are built by GM Daewoo in South Korea. Hyundai and Kia have design and engineering centers in Germany and car factories in the Czech Republic and Slovakia. Renault's Dacia brand is based in Romania and closely tied with Renault's headquarters in Paris.
"Chevrolet isn't helped by products that aren't going to set the world on fire compared with Hyundai and Kia," said IHS Automotive senior analyst Ian Fletcher.
Jonathan Poskitt, an analyst at LMC Automotive, said Chevrolet's major products are losing sales because they are getting old. "The Spark and Aveo are high-volume models for the brand, but they are past their peak market share," he said.
Chevrolet cars are not as fuel efficient as newer models from competitors. High fuel prices and tax regimes that penalize vehicles with high CO2 emissions mean that fuel economy is an increasingly important factor for sales success in Europe.
The average CO2 emissions for Chevrolet's new-car fleet in Europe was 141 grams per kilometer in 2012, according to JATO Dynamics. The figure placed Chevrolet No. 18 in a ranking of 20 manufacturers, behind BMW and Mercedes-Benz.
Opel competition
Analysts say overlapping products with GM's Opel and Vauxhall brands also hurt Chevrolet.
IHS analyst Fletcher highlighted the overlap between models such as the Chevrolet Trax/Opel Mokka and the Chevrolet Captiva/Opel Antara.
"There are certainly some mixed messages in its range," he said.
Chevrolet declined to comment for this article but Opel says the two brands do not attract cross-shoppers. "Opel and Chevrolet have deliberately been given a distinctive brand positioning and aim at different customers," it said in a statement last month. "Studies show that the risk for each brand to lose customers to the other brand is low."
Fletcher said price discounting in Europe's weak auto market has brought Opel closer to Chevrolet. Opel vehicles are priced higher but customers can end up paying similar prices to a cheaper Chevrolet after getting a significant discount.
Globally, Chevrolet is doing well. GM recently announced record first-quarter sales of 2.36 million for the brand, up 4 percent on the year before.
But Chevrolet will continue to struggle in Europe for years to come, analysts say.
IHS forecasts that Chevrolet sales will continue to fall in the region until 2016, which is when the Spark and the Cruze compact are scheduled to be replaced.
Chevrolet sales fell 3 percent to 172,000 cars in Europe last year, according to ACEA. The brand's EU sales will rise to 200,000 in 2016 on new products, IHS predicts, but not before hitting a low of 148,000 in 2015.
