Energy markets are being dragged down on speculation that the global oil glut could get worse. Nevertheless, traders can still hedge against further weakness with inverse exchange traded fund strategies.

According to Goldman Sachs Group’s latest assessment, a failure to quickly cut production now could drive oil prices to $20 per barrel, a necessary level to adequately clear the oversupply, Bloomberg reports.

“The oil market is even more oversupplied than we had expected and we now forecast this surplus to persist in 2016,” Goldman analysts including Damien Courvalin wrote in a report. “We continue to view U.S. shale as the likely near-term source of supply adjustment.”

Goldman reduced its 2016 estimate for WTI to $45 per barrel from a previous projection of $57 due to production growth from the Organization of Petroleum Exporting Countries, steady supply outside of the group and slowing global demand. The investment bank also calculated that Brent crude could average $49.5 per barrel, compared to previous forecasts of $62.

West Texas Intermediate crude oil futures were hovering around $45.2 per barrel and Brent crude oil was trading around $48.6 per barrel Friday.

“We now believe the market requires non-OPEC production to shift from our prior expectation of modest growth to large declines in 2016,” Goldman added. “The uncertainty on how and where that adjustment will take place has increased.”

The International Energy Agency also came out on Friday to predict production outside of OPEC will decline by 500,000 barrels per day to 57.7 million in 2016, with shale oil producers cutting down by 385,000 barrels per day as crude prices dip below the $50 “slams brakes” level.