S&P/ASX 300

The S&P/ASX 300 index is a market-capitalisation weighted and float-adjusted stock market index of Australian stocks listed on the Australian Securities Exchange from Standard & Poor's.

The index incorporates all of the companies in the top 200, the S&P/ASX 200 index, and an additional 100 smaller companies, making a total of about 300 components in the index. The index components are reviewed quarterly by Standard & Poor's.

ASX website including links to explanation of index methodology and current components:
http://www.asx.com.au