Electricity provider Bright Energy has announced that it is exiting the Irish market following a strategic review.
The firm, which launched in the summer of 2020, blamed increases in prices on the wholesale energy market that it claimed were impacting its operations.
"While all options were explored, Bright regrets to announce that it will cease trading in February 2022," it said in a statement.
"The difficult decision was made as a consequence of ongoing market challenges and the relentless rise in wholesale energy prices, which are more than 200% higher than when bright launched in 2020."
The Commission for Regulation of Utilities (CRU) said it has received formal notification from the firm of its intention to exit the market.
The regulator said it has now initiated the Supplier of Last Resort procedure, which will see around 1,300 remaining customers moved to Electric Ireland to ensure their supply is not interrupted.
That transfer will last for 20 days, during which period Electric Ireland is mandated to consult with the impacted customers to see what they wish to do into the future, including the option of switching to another provider.
In the meantime, the CRU said customers do not need to take any immediate action.
"While the decision by Bright Energy to exit the supply market is regrettable, the Supplier of Last Resort process ensures that this will not negatively impact customers," said CRU Commissioner, Aoife MacEvilly.
"There remain fifteen electricity and eight gas suppliers in the domestic supply market. These provide a wide range of tariffs and choices for customers to suit their needs."
An all-island firm, Bright Energy had built up a customer base of around 7,000 since launch, but near the end of last year it gave customers the opportunity to transfer to Energia in the Republic of Ireland and Power NI in the north, or an alternative provider of their choice.
"As not all customers instigated a move, Bright engaged with the Commission for Regulation of Utilities (CRU)," the firm said.
"Bright notified the CRU of its intention to exit the market and, under CRU customer protection protocols, Electric Ireland is the designated electricity supplier of last resort."
"This means that all remaining Bright customers will automatically transfer to Electric Ireland from 26 January. Electric Ireland will engage with customers directly thereafter, all of whom can be reassured that their electricity supply will not be interrupted."
Bright Energy was founded by brothers Ciaran and Stephen Devine in partnership with Maxol Group, and used a software platform and app to offer a single transparent tariff to customers, with the power supplied from green sources.
In the UK, a number of energy providers have exited the market in the last year due to the massive increases in wholesale energy costs.
Here, the last provider to exit was Just Energy which announced it was leaving in 2019 for strategic reasons to focus on its much larger businesses in the UK and North America.