Oil prices plunged to within a whisker of $10 a barrel after a major index tracked by billions of dollars in funds bailed out of near-term contracts for fear prices may turn negative again.

The abrupt decision by S&P Global Inc. to tell clients to sell their June West Texas Intermediate holdings unleashed another day of chaos in the global energy market, only days after WTI prices briefly fell below zero for the first time ever. At one point on Tuesday, WTI fell to $10.07 a barrel, down more than 20% on the day, while the July contract rallied.

“This is the latest in the exodus away from the June contract,” said Harry Tchilinguirian, head of commodities strategy at BNP Paribas, noting that the move follows “the risk of negative pricing associated with the potential saturation of storage capacity at Cushing.”

Oil’s 85% plunge has come as the coronavirus outbreak destroys demand for fuels globally. In response, the world’s biggest producers have pledged to slash daily output starting next month to balance the market, but the collapse in consumption has led to a swelling glut that’s testing storage limits worldwide.

S&P is behind the GSCI commodity index, a popular investment product tracked by pension funds and other global investors. When S&P changes the investment policy, the banks who sell the product in turn move their holdings, triggering volatile energy markets.

“This unscheduled roll is being implemented based on the potential for the June 2020 WTI Crude Oil contract to price at or below zero,” S&P said in a notice seen by Bloomberg News. A spokesperson confirmed the notice.

Exchanged traded products -- most notably the United States Oil Fund LP -- have also rolled positions from June futures into later contracts, while the Bloomberg Commodity Index said it will roll from July into September.

Since WTI traded negative last week, more than 40% of the June contract has been liquidated. Holdings of the July contract have been stable, while those on September futures have jumped by almost 20%.

While the market is being hit by financial flows, Russia warned that there will be no quick fix to low prices. The nation’s energy minister, Alexander Novak said Tuesday that the oil market may only start to rebalance in the second half. Prior to the output cuts, which begin on May 1, supply from the Organization of Petroleum Exporting Countries climbed to over 31 million barrels a day, according to Geneva-based tanker tacker Petro-Logistics.

“This is the most extreme stress it has been put under,” said Paul Horsnell, head of commodities strategy at Standard Chartered, referring to WTI prices.

--With assistance from James Thornhill, Sharon Cho and Grant Smith.

This article was provided by Bloomberg News.