(b) That's wrong. Some public companies choose to enter into a contract with the Australian Securities Exchange (ASX) so that the company's shares can be listed and publicly traded on the stock market operated by the ASX. Such companies are referred to as listed companies.

Only public companies can be listed on the ASX, and not all public companies choose to do so. The ASX provides a highly organised and very liquid (easily tradable) market in shares, which makes such shares attractive to investors.

To be listed, a company must meet the criteria set down by the ASX. For example, a company must have a constitution that accords with the ASX rules; must publish a 'prospectus' containing information about the company that investors would need to know about the company, and must prove that the company is financially viable.

Listed companies are subject to special disclosure requirements and must pay an annual fee to the ASX.