Shares of Caterpillar tumbled as much as 8 percent to a five-year low, pulling down the sector and knocking as much as 37 points off the Dow Jones industrial average (.DJI). Peoria, Illinois-based Caterpillar, the world’s biggest construction and mining equipment maker, has also been hit by a slowdown in industrial activity in China. “The company has shown a lack of revenue growth in the last few years (and) earnings are in a decline,” he said.