One of the key roles of the Commission is to ensure markets in New Zealand are competitive, including by investigating anti-competitive behaviour and enforcing compliance. Investigations may involve gathering publicly available information, requesting information on a voluntary basis or compulsory basis, conducting interviews, and executing search warrants. The Commission has a range of enforcement options including the provision of compliance advice or warning letters and by prosecuting a person or business in the High Court. The Commission is responsible for enforcing prohibitions against "restrictive trade practices" (anti-competitive behaviour or conduct that reduces competition), which includes (for example) cartels or price-fixing behaviour, taking advantage of market power, or resale price maintenance.