U.S. shale oil producers lost more than $30 billion in the first half of 2015 due to a drop in oil prices. According to data from Factset, U.S. independent oil and gas companies recorded cash outflow at about $32 billion in the six months to June.
The aggregate net debt of U.S. oil and gas companies jumped to $169 billion by June 2015 from $81 billion at the end of 2010, according to Factset.
"The capital markets have been so strong and so open for these companies that a lot of them were able to raise a lot of debt," said Terry Marshall, Moody's Senior Vice President.