Cardiff Energy Supply has ceased trading and SSE Energy Services has been chosen by Ofgem to take over its customers, which number fewer than 1000.
Cardiff Energy Supply provided gas to 815 households and SSE said it would honour their credit balances.
SSE has already taken on 17,000 customers from Brilliant Energy and Northumbria Energy under the Supplier of Last Resort mechanism. Those companies ceased trading earlier this year.
SSE said, “The current energy market conditions are proving tough, forcing suppliers to offer unsustainably low prices to attract customers. A staggering thirteen suppliers have ceased trading in the last couple of years. The Supplier of Last Resort process works well for those customers whose supplier goes under but recent supplier insolvencies have left an estimated £170 million in unpaid bills – a cost ultimately picked up by customers of responsibly run suppliers.”