The soon-to-expire May contract for the U.S. oil benchmark marked history on Monday, finishing deeply in negative territory and implying that investors will need to pay buyers to take delivery of crude oil, reflecting a growing glut of crude and a lack of storage space.

West Texas Intermediate crude for May delivery US:CLK20 CL.1, -5.27% finished down $55.90, or 306%, at negative $37.63 a barrel. The May contract expires on Tuesday.

The one-day plunge is the largest on record going back to 1983, and also the lowest level for a contract on record, according to Dow Jones Market Data.

The unprecedented drop in the nearby contract reflects traders scrambling to exit long positions that would require them to take physical delivery of crude amid dwindling storage space. It also reflects a convergence with the physical spot price for oil.

Read:Why oil prices just crashed into negative territory — 4 things investors need to know

“It’s like trying to explain something that is unprecedented and seemingly unreal!,” wrote Louise Dickson, oil markets analyst Louise at Rystad Energy, in emailed comments.

“The most simple explanation for negative oil prices is that midstream players are now paying ‘buyers’ to take oil volumes away as the physical storage limit will be reached. And they are paying top dollar!” the analyst said.

The June contract US:CLM20, which is the most actively traded, ended down $4.60, or 18.3%, at $20.03 a barrel.

“The collapse…is mostly a reflection of traders rolling contracts to June as no one wants to take delivery because storage capacity is getting close to being reached,” said Edward Moya, senior market analyst at Oanda, in a note.

The ever-widening discount for May versus the June contract reflects “all the bearish supply and demand drivers that remain permanently in place,” he said.

“While we are probably setting the stage for a significant bottom in oil, it does not matter for the May futures contract that will be delivered into a nightmarish bearish situation,” said Phil Flynn, market analyst at Price Futures Group, in a note. “Not only has demand ground to a standstill, the impact of oil cuts from OPEC+ also will not start in time for the current delivery.”

The trading action comes after the May contract posted a 19.7% weekly loss on Friday.

WTI contracts for later delivery have traded at much higher prices than the front-month May contracts. The steep upward slope for prices in later months in crude, a condition known as contango, underlines the dearth of storage of crude in recent weeks as the coronavirus wreaks havoc on global demand for oil.

The expiration of the May contract and the fundamental demand problems have combined to put outsize pressures on the energy sector.

“Price discovery is complicated, more so than usual, by the soon-to-expire WTI NYMEX front-month contract for May 2020,” wrote Stephen Innes, global chief market strategist at AxiCorp, in a Sunday research note.

“Even more so as the near-term prices are trading massively discounted due to storage premiums getting packed in the far dates, creating very squeezy conditions on the expiring contract as final day settlement (FDS) looms,” he wrote.

Monthly reports from the Organization of the Petroleum Exporting Countries and the International Energy Agency have underscored a period of flagging appetite for crude, even as major oil producers have forged a historic pact to curb output by some 10 million barrels a day, in an effort to end a price war between Saudi Arabia and Russia and stabilize prices that have been swooning.

In addition to OPEC and its allies trimming production, there is also the possibility on April 21 that the Railroad Commission of Texas, which regulates the oil-and-gas industry in the state, could move to limit output in the region.

Reports have also suggested that the Trump administration may provide further incentive by offering to pay producers to keep crude in the ground.

Meanwhile, Brent crude for June delivery UK:BRNM20 the international benchmark, finished down $2.51, or 8.94%, at $25.57 a barrel, after falling 10.8% last week. Brent is more seaborne than WTI, which is often moved via pipelines, is somewhat less constrained by immediate storage worries.

In other energy trading, May gasoline US:RBK20 lost 4.24 cents, or 6%, to end at 66.83 cents a gallon, while June heating oil US:HOM20 shed 6.85 cents, or 7.2,%, to close at 88.78 cents a gallon.

May natural-gas futures US:NGK20, meanwhile, gained 17.10 cents, or 9.75, to $1.9240 per million British thermal units.