Clydebank-based Total Energy is set to collapse "within weeks".
In November, the company stated that it was looking to secure "long-term funding for growth" in order to return to profitability.
However, Sky News reported that Together Energy has not yet been able to find that crucial investment and is "likely to run out of money" later in January, without an emergency capital injection.
Together Energy was understood to be working with advisers at Alvarez & Marsal to raise additional capital.
It is a supplier to more than 170,000 homes and has 350,000 accounts.
According to its most recently-available accounts, for the 12 months to the end of October 2020, the business posted a pre-tax loss of £4.1m.
The funding search comes after energy supplier Bulb was put into special administration in November.
It was by far the largest of more than 20 suppliers to collapse since the start of the 2021, amid the soaring price of gas.
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