A slowdown in China is hurting industrial equipment giant Caterpillar — and investors aren’t happy. Caterpillar reported fourth-quarter earnings Monday morning that missed Wall Street’s forecasts. The company said sales in its Asia/Pacific unit were down 4% from a year ago, primarily “due to lower demand in China.” It was Caterpillar’s biggest earnings miss in 10 years, according to research firm Bespoke Investment Group. Caterpillar issued an earnings outlook for 2019 that was also lower than Wall Street forecasts. Shares of Caterpillar\n \n (CAT) fell more than 8% and the broader market tumbled as well. Futures were already pointing to a loss at the opening bell but they fell further after Caterpillar\n \n (CAT), which is a Dow component, reported results. The market fell further after chip company Nvidia\n \n (NVDA) warned that sales would be weaker than expected, because of a slowdown in China. Caterpillar chairman and CEO Jim Umpleby said in the earnings release that the company was now assuming “a modest sales increase” for this year, in part because of the “macroeconomic and geopolitical environment.” Weakness in China is problematic for Caterpillar. China has spent an enormous sum on infrastructure over the past few years — and has bought a lot of Caterpillar bulldozers, excavators and tractors in the process. China accounted for between 5% and 10% of its total sales and 10% to 15% of its construction unit’s revenue, Caterpillar Chief Financial Officer Andrew Bonfield said during the company’s last earnings conference call in October. The Chinese economy has lost momentum in recent months, and companies with big exposure to the world’s most populous nation have been hurt. Apple\n \n (AAPL) has already warned about weaker iPhone sales in China. Tire maker Goodyear\n \n (GT) and FedEx\n \n (FDX) have also said that softness in China was hurting their profits. The continued drama surrounding trade talks between the United States and China could also complicate matters for Caterpillar. Its impact from tariffs on steel and other materials was about $40 million in the third quarter, and a little more than $100 million for the full year, the company said. Caterpillar did not give any update Monday in its earnings release about the impact from tariffs. But during a conference call with analysts Monday morning, Umpleby said that Caterpillar expects the overall China market will be flat this year after two years of strong growth.