The Corporations Legislation Amendment Act 1990 is a Commonwealth amending Act. Its long title says it is an Act to amend the Corporations Act 1989 and related legislation. The practical significance of the Act comes from what Part 2 says it was designed to do.
Section 4 states that Part 2 changed the Corporations Act 1989 from an Act relying on Commonwealth powers and intended to apply of its own force throughout Australia into a law for the government of the Australian Capital Territory in relation to corporations, securities, the futures industry and some other matters. It also says the amendments were designed so the resulting Corporations Law could be applied by the States, including the Northern Territory, as their own law, making it suitable for use as a uniform law in all States and internal Territories.
That means this Act is best understood as part of the legal architecture of the old national corporations scheme. For most business owners, it is not a standalone operating manual. Its value is in explaining how the Corporations Law framework was built, why older records use that language, and why historical company documents were often drafted as though there were one national corporations law even though the legal mechanism was more technical.