Calpine, the US energy group, is set to complete its second sell-out high yield debt deal in four weeks, in the latest sign of how the debt markets are rescuing struggling energy companies.

Calpine is expecting to raise $1.8bn (€1.6bn) in junk bonds and loans notes this week in a deal managed by Goldman Sachs. It follows a highly structured $800m bonds issued via Morgan Stanley in June.