Neon Reef and Social Energy Supply have become the latest domestic suppliers to cease trading.
Two more energy suppliers with a combined total of 35,500 customers have ceased trading amid a backdrop of high wholesale gas prices.
Neon Reef and Social Energy Supply have stopped trading, according to the energy regulator Ofgem.
Neon is the larger of the two with 30,000 domestic customers.
It means that more than 20 suppliers have now ceased operations since August, affecting more than two million customers overall.
Those households have been moved to new suppliers, but generally on more expensive tariffs.
Ofgem said that customers of Neon and Social Energy Supply should take meter readings and wait for more information regarding their new supplier.
“Do not switch in the meantime. You can rely on your energy supply as normal. We will update you when we have chosen a new supplier, who will then get in touch about your tariff,” said Neil Lawrence, director of retail at Ofgem.
“If you have credit on your account the funds you have paid in are protected and you will not lose the money that is owed to you.”
Suppliers are under pressure from high wholesale gas prices, and also by their inability to pass on extra costs to customers protected by fixed tariffs, or the regulator’s price cap.
Wholesale gas prices in the UK surged by 17% on Tuesday after the German energy regulator suspended the approval process for a new Russian pipeline.
The pipeline which goes under the Baltic Sea is expected to double the amount of gas that Russia sells to Europe.