Saudi Arabia is producing so much oil some analysts have speculated whether it might even lead to negative prices.
US stocks were down again, with the Dow Jones Industrial Average losing 6.3% and the S&P 500 down 5.2% on concerns over the impacts of the Covid-19 pandemic.
Copper was down 7.8% in midweek trade to $4729.50 per tonne, the biggest one-day loss since 2008 and the lowest level since late 2016.
Gold also took a hit, down 3.1% to $1477.90 an ounce, a new 2020 low.
Earlier in the week, after the market closed for the day, the New York Stock Exchange announced it would temporarily shift to all-electronic trading.
"The decision to temporarily close the trading floors represents a precautionary step to protect the health and well-being of employees and the floor community in response to the coronavirus pandemic," the NYSE said.
"Our markets are fully capable of operating in an all-electronic fashion to serve all participants, and we will proceed in that manner until we can reopen our trading floors to our members," said NYSE president Stacey Cunningham. She added that all NYSE markets "will continue to operate under normal trading hours despite the closure of the trading floors".