“Chinese and international project developers are putting their orders on hold as modules get cheaper,” Yali Jiang, an analyst at Bloomberg New Energy Finance, said in a research note, projecting that by the end of the year, module prices will slide to 24 cents per watt or down 35% from 37 cents at the end of 2017.

Tan includes a 45.6% tilt toward U.S. solar companies, along with 21.1% China, 9.5% Spain, 8.6% Germany, 4.7% Norway, 4.4% Canada, 3.9% Switzerland and 2.3% Hong Kong.

Other renewable energy-related ETFs that include solar exposure have also been weakening this year. Year-to-date, the iShares Global Clean Energy ETF (NYSEArca: ICLNfell 2.8%, Vaneck Vectors Global Alternative Energy ETF (NYSEArca: GEX) dropped 1.2% and Invesco Global Clean Energy Portfolio (NYSEArca: PBD) declined 7.5%.

For more information on the photovoltaic panel industry, visit our solar category.