Copper-related exchange traded products plunged Wednesday, with the copper metal set to dip into bear-market territory, as concerns over a global economic slowdown weighed on the demand outlook.

On Wednesday, the iPath Bloomberg Copper Subindex Total Return ETN (NYSEArca: JJCTF) declined 5.2%, United States Copper Index Fund (NYSEARCA: CPER) fell 3.9% and iPath Bloomberg Copper Subindex Total Return ETN (NYSEArca: JJCB) decreased 4.7%.

Meanwhile, Comex copper futures dropped 4.0% to $2.575 per pound, it’s lowest level in over a year. Since June 8, copper futures have plunged 22.0% from $3.33 per pound.

Metals, especially copper, are considered an economic indicator by some investors due to their widespread usage in major economic activities, such as construction and manufacturing. The metal is also closely associated with strength in China, which makes up over half the world’s demand of certain industrial metals and is currently in a trade dispute with the U.S., the Wall Street Journal reports.

Tariffs & Chinese Economy

Market observers are concerned that tariffs will hobble the Chinese economy and diminish demand for materials have hurt metals, like copper. Market anxiety was renewed Tuesday after data showed Chinese spending on fixed assets like factory machinery and public-works projects hit its lowest point in nearly two decades over the first seven months of the year.

“There are still concerns of a slowdown in the second half of 2018 despite the stimuli, and the trade conflict with the U.S. shows no signs of cooling,” Vivienne Lloyd, senior analyst at Macquarie, told the WSJ.

Related: Copper ETPs’ Underperformance is Worrisome for the Broader Economy

Furthermore, some are worried that further weakness in emerging economies, like Turkey, and the rising strength of the U.S. dollar – metals priced in USD have become pricier for foreign buyers – will cut down commodity consumption.

“It’s all one story. Continued macro concerns over trade have now added Turkey into the mix, and that adds to the premise of synchronized global growth being steadily undermined,” Oliver Nugent, a commodities strategist at ING, told the WSJ.

For more information on the copper market, visit our copper category.