In December Octopus Energy took over the supplier, which collapsed in 2021, when the government said it would provide up to 4.5 billion pounds ($5.4 billion) to fund the deal - although the extent of government support could be less, depending on energy prices.
The three other energy suppliers had argued the government had unlawfully committed billions of pounds of taxpayers' money to prop up Bulb, without considering the potential impact on the wider energy market.
In its ruling, the High Court in London rejected the firms' application for a judicial review of the decision.
(Reporting by Sarah Young and Michael Holden; editing by William James)
