Dated Brent was assessed at $18.86 on Thursday, according to S&P Global Platts, far below futures prices, and real cargoes are trading at even steeper discounts.

With the recent output-cuts deal by OPEC and its partners failing to revive prices, Saudi Arabia and Russia have said they’ll “continue to closely monitor the oil market and are prepared to take further measures jointly with OPEC+ and other producers if these are deemed necessary.” Saudi Aramco said Friday that it will reduce supply to 8.5 million barrels a day from May 1.

“We’re seeing record cuts, but still not enough to bring the market even close to balance,” said Warren Patterson, head of commodities strategy at ING Bank NV. “Even OPEC’s own numbers showed that. It’s a continuation of the story.”

As prices have fallen, investors have poured more than $1 billion into the U.S. Oil Fund ETF so far this week. At Thursday’s close, the fund held more than a quarter of all the June WTI contracts. As of Friday, the fund will now hold 20% of its contracts in the second WTI futures month.

“The amount of buying in Oil ETF has been staggering,” hedge-fund manager Pierre Andurand wrote in a tweet.