Where restrictions on business practices are imposed by statute, they cannot constitute agreements between or decisions of firms for purposes of section 4(1) of the Competition Act, regardless of their competitive effects. Statutory prohibitions are decisions of the lawmaker (Parliament), not of market participants. The Competition Tribunal has jurisdiction to interpret statutes other than the Competition Act to the extent necessary to determine the source of challenged restrictions and whether those restrictions fall within the scope of the Competition Act. Where a preliminary issue is potentially dispositive and can be determined without extensive evidence, the Tribunal should decide that issue before proceeding to hear evidence on the merits. In the context of the Health Professions Act 56 of 1974, the prohibition on lay ownership of optometry practices flows from sections 17, 34, and 39 of that Act, which restrict the practice of health professions to registered natural persons, and from the limited scope of the ministerial exemption under section 54A, which permits only corporate practices where all shareholders and directors are registered practitioners. Rule 8 of the Ethical Rules and paragraph 2 of the Policy Document merely explain these statutory restrictions rather than creating independent restrictions.