Ann: Trading Halt, page-119

It's incredibly unlikely they would go into a trading halt to announce that "something is happening soon" as that type of announcement isn't material to the share price in any way. You generally only go into a trading halt because of the release of a market sensitive announcement that is likely to have a significant share price impact. I think a previous poster in one of the threads noted that the wording of "providing an update in relation to..." is common in IVZ announcement and appears to just be the way they word them.