You were right whi55l. Bulletin just published on the CommSec site:
"Site news
Issue with updating data in your portfolio position in IE 15 Apr 2010
If you are using Internet Explorer and have two or more CommSec accounts when logging in with a Client ID, the data in your portfolio might not be updating due to a recent Microsoft security software update.
To resolve this issue clear your temporary internet files by following the steps below:
IE 6: Within your Internet Explorer browser click on Tools > Internet Options > Delete Files. Click on Delete all Offline Content followed by OK. Proceed to click on Delete Cookies and press OK.
IE 7: Within your Internet Explorer browser click on Tools > Internet Options. Under the browsing history press Delete. Then click on the Delete Files button for Temporary Internet Files and Cookies.
IE 8: Within your Internet Explorer browser click on Tools > Internet Options. Make sure Preserve Favourites Website Data is not ticked, before selecting Temporary Internet Files and Cookies. Press Delete at the bottom of this screen."
