Opening takes place at 10:00 a.m. AEST and lasts for approximately 10 minutes.
ASX shares open in five groups, depending on the starting letter of their ASX code:
Group 1 – 10:00:00 a.m. (+/- 15 secs). Letters A-B (e.g. ANZ and BHP).
Group 2 – 10:02:15 a.m. (+/- 15 secs). Letters C-F (e.g. CBA, DJS, EXT, and FMG).
Group 3 – 10:04:30 a.m. (+/- 15 secs). Letters G-M (e.g. GNC, HDF, ILU, JBH, KAR, LYC, and MYR).
Group 4 – 10:06:45 a.m. (+/- 15 secs). Letters N-R (e.g. NAB, OST, PDN, QAN, and RIO).
Group 5 – 10:09:00 a.m. (+/- 15 secs). Letters S-Z (e.g. SEK, TLS, UGL, VBA, WBC, and ZIM).
The opening time is randomly generated and occurs up to 15 seconds either side of the times shown above. For example, Group 1 may open at any time between 9:59:45 a.m. and 10:00:15 a.m. The “match” (explanation below) also occurs during the open to determine the opening price of a share.