Energy regulator Ofgem is readying itself for a new wave of supplier collapses.
At least four suppliers were reported to be in talks with Ofgem on Tuesday, according to Sky News.
The companies were understood to be discussing joining the Supplier of Last Resort (SOLR) system.
Some companies could make public a decision to cease trading as early as Wednesday, sector sources said.
One company is believed to include Pure Planet, whose collapse could leave 250,000 customers requiring a new supplier.
Other small suppliers thought to be potentially at risk of failure have included Ampower, Zebra Energy and Neon Reef, according to analysts.
More than 1.7m households have had their supplier switched since the start of August as companies have succumbed to soaring prices.