The Australian Securities Exchange (ASX) is the primary stock exchange in Australia and began as separate state-based exchanges established as early as 1861. Today trading is all-electronic and the exchange is a public company, listed on the exchange itself.

It came about by a merger of the Australian Stock Exchange and the Sydney Futures Exchange in December 2006.

The biggest stocks traded on the ASX, in terms of their market capitalisation, include mining companies, banks and the national telephone carrier Telstra Corporation.

The major market index is the (Standard & Poors credit ratings) S&P/ASX 200, an index made up of the top 200 shares in the ASX. This replaced the previously significant All Ordinaries index, which still runs parallel to the S&P ASX 200. Both are commonly quoted together. Other indices for the bigger stocks are the S&P/ASX 100 and S&P/ASX 50.

The ASX is a public company, and its own shares are traded on the ASX. However, the corporation's charter restricts maximum individual holdings to a small fraction of the company.

While the ASX regulates other listed companies listed on the ASX, it cannot regulate itself, and is regulated by the Australian Securities and Investments Commission (ASIC).

ASX has a pre-market session from 07:00am to 10:00am [AEST] and a normal trading session from 10:00am to 04:00pm [AEST] .