Mercury NZ Limited is a New Zealand electricity generation and multi-product utility retailer of electricity, gas, broadband and mobile telephone services. All the company's electricity generation is renewable. Mercury has a pre-paid electricity product sub-brand GLOBUG. Mercury Energy is also the largest electricity retailer in New Zealand.

Entrust, formerly named Auckland Energy Consumer Trust (AECT) prior to June 2016, is a trust for electricity consumers in Auckland, New Zealand. Formed in 1993 as sole owner of the original Mercury Energy Limited, it is now majority owner of electricity and gas distributor Vector Limited, a child of the original Mercury, the other child being the retailing division of Mercury Energy. The Trust will be wound up in 2073 and its assets transferred to the local government authority or authorities in the Trust district. There have been calls for the Trust to be wound up sooner.