Igloo Energy supplies gas and electricity to around 179,000 domestic customers, Symbio supplies around 48,000 domestic customers and a small number of non-domestic customers and Enstroga supplies around 6,000 domestic customers.
Under Ofgem’s safety net, the energy supply to all affected customers will continue and credit balances will be protected.
Domestic customers will also be protected by the energy price cap when being switched to a new supplier.
Customers of Enstroga, Igloo Energy and Symbio Energy will be contacted by their new supplier, which will be chosen by Ofgem.
Ofgem advised customers of the three firms to wait until a new supplier has been appointed and has made contact before looking to switch and to take a meter reading.
The three firms are the latest to collapse in recent weeks amid an unprecedented increase in global gas prices.
This means that nine small UK energy suppliers have gone bust since the start of September.
It comes after failures by People’s Energy, Green Supplier Ltd, Utility Point, PfP Energy, MoneyPlus Energy, and Avro Energy.
Ofgem said it was working closely with the Government and industry to make sure customers continued to be protected this winter.
Neil Lawrence, director of retail at Ofgem, said: “Ofgem’s number one priority is to protect customers. We know this is a worrying time for many people and news of a supplier going out of business can be unsettling.
“I want to reassure customers of Enstroga, Igloo Energy and Symbio Energy that they do not need to worry. Under our safety net we’ll make sure your energy supplies continue. If you have credit on your Enstroga, Igloo Energy or Symbio Energy account, the funds you have paid in are protected and you will not lose the money that is owed to you.
“Ofgem will choose a new supplier for you, and while we are doing this our advice is to wait until we appoint a new supplier and 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.
“Any customer worried about paying their energy bill should contact their supplier to access the range of support that is available.”
Justina Miltienyte, energy policy expert at Uswitch.com, said: “The difficult wholesale energy market situation brings more bad news every week and now another three suppliers have gone into administration.
“In total, 233,000 more customers will be joining the almost two million who have already been displaced by their energy provider this year and we may not have seen the end to this situation.
“Many customers will be worried, but those impacted by this news can be reassured that their energy supply will continue as normal and credit balances will be protected.
“It’s important that all affected customers hold tight for now while they are moved to a new supplier appointed by Ofgem. They should wait for the dust to settle on the current situation before weighing up whether there are any better deals available elsewhere.
“We recommend that customers make a note of their meter readings now, and again when contacted by their new supplier, to ensure bills are accurate.”