Freeport-McMoRan Inc. may lose its investment-grade rating after Moody’s Investors Service placed the metals and energy producer’s debt under review for possible downgrade.

Copper and oil prices have plunged on increased production and slowing demand, and the outlook for further price weakness will “result in insufficient free cash flow in 2016 to de-lever the balance sheet as previously expected,” Moody’s said in a statement Tuesday. Moody’s currently ranks the debt Baa3, one level above junk.

Moody’s said the review will focus on further steps Freeport can take to support its balance sheet, as well as risks surrounding plans to construct a new copper smelter in Indonesia. Noble Group Ltd., the commodity trader battling criticism of its accounting, had its credit rating cut to junk by Moody’s last week on concerns about the company’s liquidity amid a broad downturn in prices for energy and raw materials.

"At this time no meaningful catalyst is seen that will improve the overall market dynamics given weak global growth rates and slowing demand in China,” Moody’s said in the statement on Freeport.

Standard & Poor’s and Fitch both have investment grade ratings on Freeport. Standard & Poor’s has a negative outlook on the company’s debt, while Fitch views it as stable.

Freeport invested heavily in the oil and gas sector in 2013 with the acquisitions of McMoRan Exploration Co. and Plains Exploration & Production Co., swelling its debt just ahead of a downturn in energy prices. Activist investor Carl Icahn has been pressuring the company to cut costs, rein in executive compensation, and shrink operations with high-cost production. Last week, the company said its co-founder James “Jim Bob” Moffett would be stepping down.

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