New York

HIGHLY-LEVERAGED US energy companies are struggling to carry out debt swaps as part of their survival strategy because plummeting oil and gas prices make investors either avoid such deals or demand tougher terms.

Last year, at least 10 exploration and production companies, including California Resources Corp, managed to ease financial pressure by persuading investors to accept some losses on their bond holdings in return for new debt that often matures later and offers better collateral.