Despite being on the wrong side of the oil trade, some investors have continued allocating capital to energy exchange traded funds even as oil volatility climbed and prices tumbled.

Even with Thursday’s 4.1% jump, the United States Oil Fund (NYSEArca: USO)is down 47% over the past six months, but that has not prevented investors from flocking to the ETF.

“A total of $4.21 billion has been sent into the four biggest U.S. oil ETFs since October. USO attracted $1.15 billion in January,” reports Morning Zhou for Bloomberg.

As has been previously noted, USO’s assets under management and shares outstanding tallies often rise as oil prices fall because some traders opt to short that ETF rather than inverse equivalents. When short sellers borrow shares of USO, the ETF’s shares outstanding count rises. [Energy ETFs Adding Assets]

“The number of U.S. Oil Fund shares on loan to short sellers was 31.3 million as of Jan. 15, or about 93 percent of average daily volume, according to exchange data. Short interest was as much as eight times daily volume in June,” according to Bloomberg.

However, amid a raft of short covering, USO is up 5% over the past month and has garnered nearly $1.1 billion of new assets. USO is not the only ETF that has been the object of investors’ affection for betting on an energy rebound.

Since the start of 2015, the Energy Select Sector SPDR (NYSEArca: XLE) has seen inflows of over $1.2 billion, good for the highest total among all sector ETFs. That despite the energy sector trading at a noticeable premium to the broader market.

“Profit expectations have fallen dramatically, which in turn has pushed the sector’s P/E ratio higher even as stock prices have declined. Obviously momentum isn’t in the Energy sector’s favor, but stocks appear attractive in terms of valuation if–and this is a big if–the depressed profitability (Return on Equity) forecast for this year and next is temporary, rather than a ‘new normal’ reflecting abundant new supplies from shale,” said AltaVista in a new research note. [Energy ETF Ebullience]

Traders have also embraced leveraged ETFs as an avenue for participating in an energy sector rebound. As of Feb. 3, year-to-date inflows to the Direxion Daily Energy Bull 3X Shares (NYSEArca: ERX) reached nearly $172 million, helping boost the ETF’s shares outstanding count by 66%. ERX attempts to deliver three times the daily performance of the S&P Energy Select Sector Index, XLE’s underlying index.

Energy Select Sector SPDR