Crude oil and commodity-related exchange traded funds surged back into a bull market, rallying on lower U.S. output expectations and the Organization of Petroleum Exporting Countries hinting at diminished output.

On Monday, the United States Oil Fund (NYSEArca: USO), which tracks West Texas Intermediate oil, increased 5.9% and the United States Brent Oil Fund (NYSEArca: BNO), which tracks Brent crude oil futures, gained 5.3%. Since the August 24 low, USO has surged 27.6% and BNO jumped 25.3%. [Oil ETFs Surge As Shorts Get Blindsided]

Additionally, leveraged oil ETFs also shot up on the action. On Monday, the ProShares Ultra Bloomberg Crude Oil (NYSEArca: UCO), which takes two times or 200% daily performance of WTI crude oil, was up 12.7% and the VelocityShares 3x Long Crude ETN (NYSEArca: UWTI), which tracks three times or 300% the daily performance of WTI crude, was 20.2% higher. [Investors Capitalize on Oil Swings with Leveraged ETFs]

Oil prices were gaining on two supply concerns. First off, according to the U.S. Energy Information Administration, U.S. oil output is lower after depressed energy prices dragged on uneconomic new investments and companies struggle to turn a profit, reports Nicole Friedman for the Wall Street Journal.

The EIA downwardly revised its estimates for production in the first five months of the year by between 40,000 and 130,000 barrels per day each month. Moreover, it said that June production declined 100,000 barrels per day to 9.3 million barrels a day.

Oil prices rose to a one-month high after OPEC said it will be talking to producers to achieve “fair prices,” reports Mark Shenk for Bloomberg.

“The market turned around on two pieces of news,” Phil Flynn, senior market analyst for Price Futures Group Inc., told Bloomberg. “The EIA cut its U.S. output estimates and OPEC says its ready to talk to others about cutting output.”

Iran’s oil minister Bijan Zangaeh stated Saturday that there was a consensus within OPEC members that $80 per barrel was an equitable price, mirroring previous calls by Iraq and Venezuela, reports Nicole Friedman for the Wall Street Journal.

WTI crude oil futures were up 6.1% Monday, trading around $48.0 per barrel. Meanwhile, Brent crude oil was 5.2% higher, hovering around $52.7 per barrel.

Energy prices are bouncing off a six-year low as an oversupply of crude oil depressed prices over the past year, with many market observers expecting years before a full recovery in prices.

United States Oil Fund

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Max Chen contributed to this article.