Mercedes-Benz Group AG shares fell the most in four years after a deepening slowdown in China prompted the world’s biggest luxury-car maker to cut its outlook.

Mercedes-Benz Group shares fell 8% on Friday after the German carmaker made another cut to its full-year guidance, citing a slowdown in car sales caused by a slump in China’s economy.

Mercedes-Benz Group cut its financial forecast for the year due to a rapid deterioration of its business in China -- the company's biggest market. The Chinese market has cooled further, hurting sales of Mercedes' most expensive models like the S-Class and Maybach sedans.