The Commerce Amendment Act 2022 made changes to section 36 of the Commerce Act 1986, which is the provision dealing with misuse of market power. The amended section 36 will address misuse of market power by prohibiting a business with a substantial degree of power in a market from engaging in conduct that has the purpose, effect, or likely effect of substantially lessening competition in a market. The changes to section 36 will come into effect on 5 April 2023 and are designed to better enable the Commission to take enforcement action against misuse of market power. We have drafted Misuse of Market Power Guidelines (draft Guidelines) that explain how the Commission will assess conduct under the amended section 36, including our approach to applying the ‘substantial lessening of competition’ test to unilateral conduct.