British Gas made no money from its business to business energy supply division in the first half of this year.
The firm shed 30,000 UK business customers and posted a profit of £0 versus £31m the prior year.
Publishing first half results, parent company Centrica said the business continued to rebuild its reputation following fallout from its billing system implementation some years ago.
The company said it expected to return to profit for the full year and will focus activities on higher value small and medium-sized companies, which are generally more profitable for suppliers than large industrial and commercial customers.
The firm said it will continue building relationships with brokers, which hold significant influence over the business to business market.
British Gas lost 377,000 household energy accounts with domestic energy supply profits falling 26% to £381m.
The company has urged policymakers to make small suppliers pay social and environmental levies, suggesting they have an unfair advantage over large market incumbents.
Currently, small suppliers do not have to add the cost of some government policies to their bills. As these costs increase, large firms argue, that creates a market distortion.
As small suppliers continue to take customers from large suppliers, the suggestion is that distortion becomes amplified.
While large utilities face challenging times and significant debt, Centrica said it was on track to deliver £250m in efficiency savings for the full year and had cut its net debt by 22% over the last 12 months.
Markets reacted positively to the announcement. Centrica’s share price rose 2% in early trading.