Oil and natural gas producer Ultra Petroleum has filed for bankruptcy protection in the US in order to reduce its debt amid plunging oil and gas prices.
According to a court filing, the firm has listed assets in the range of $1bn to $10bn and liabilities in range of $1bn to $10bn.
Previously, the company had disclosed that it has a debt of $3.9bn.
Ultra Petroleum main assets include gas-producing properties in Wyoming, as well as some assets in Pennsylvania and crude oil properties in Utah.
Bloomberg cited Ultra Petroleum CFO Garland Shaw as saying in a filing: "The low commodity prices, and especially the low natural gas prices that prevailed throughout 2015 and have continued through the first four months of 2016 have had a devastating impact."
Shaw said that the bankruptcy protection comes after the company failed to sign a debt-restructuring deal with its lenders and bondholders.
The drop in oil price has also affected publicly traded oil and natural gas firm Midstates Petroleum, which also filed for Chapter 11 bankruptcy protection in Texas.
Midstates filed for bankruptcy upon signing a $2bn debt-for-equity swap deal with its lenders and bondholders.
Midstates president and CEO Jake Brace said: "The sharp decline in oil prices since 2014 has put much of the oil and gas industry in financial difficulty.
"While our premier Mississippian Lime assets can achieve solid rates of return in the current price environment, our highly leveraged balance sheet has severely limited our ability to sustain our operations during an extended period of low prices.
"We believe that by restructuring the Company’s balance sheet now, we will be able to navigate through this downturn and create a much stronger and more financially sound company that will have long-term benefits for our employees, vendors, and all our stakeholders."