Ofcom has fined Shell Energy £1.4 million for breaching the regulator's rules after failing to let close to 73,000 people know that their contracts were coming to an end.
Shell is working with US investment bank Lazard Ltd. to evaluate options including a sale of its European retail gas and power business, according to people familiar with the matter.
Oil giant Shell has raised questions about the future of its energy supply business which employs thousands of people in the UK as companies continue to struggle in a tough market.
Shell gave its British retail energy arm roughly £1.2 billion ($1.5 billion) of financial backing this year to survive wild swings in natural gas and power prices.
Royal Dutch Shell has renamed First Utility as Shell Energy as it announced it has switched all of the supplier's British residential customers to 100% renewable electricity.