The Guggenheim Solar ETF (NYSEArca: TAN) is down more than 8% over the past month and that decline is luring short sellers to the largest solar exchange traded fund at a fevered pace.

Tumbling shares of SunEdison (NasdaqGS: SUNE) are tempting traders to establish bearish positions on TAN and other solar stocks. Chief Executive Officer Ahmad Chatila has laid off workers and slowed growth to assuage investor fears about the company’s financial liquidity.

SunEdison spent more than $6 billion on acquisitions over the past year, which has led to funding concerns for additional projects. Due to its ballooning costs, the firm cut 15% of its workforce last month, Reuters reports. In light of its diminishing coffers, the company has stated that there were “no assurances” it would raise the $6.5 billion to $8.8 billion needed to fund the construction of renewable energy assets through 2016.

“Bearish bets are stacking up in stocks in an exchange-traded fund tracking the energy companies, with the average proportion of shares borrowed and sold above 7 percent of shares outstanding, according to data from Markit Ltd. That’s the highest for the group since February and almost three times the ratio in Standard & Poor’s 500 companies,” reports Oliver Renick for Bloomberg.

The world is adding more capacity for clean energy each year than for coal, natural gas and oil combined, and the emerging markets has been crucial factor in the new developments. Last year, emerging countries invested a record $126 billion in clean energy, up 39% year-over-year.