Power company Mighty River Power is throwing its weight behind a single brand and changing its name to Mercury.
The company already uses Mercury for its retail operations in Auckland.
Its chief executive Fraser Whineray said that brand was better known than Mighty River, so it made sense to use it instead.
He said the one-time cost of rebranding would be offset by the long-term savings arising from having a single brand.
Mighty River will progressively rebrand its business, while retaining the Metrix brand name for its metering business.