The reason is this: "An entity should consider requesting a...

The reason is this: "An entity should consider requesting a trading halt whenever it is necessary to manage its continuous disclosure obligations under Listing Rules 3.1-3.1B and to avoid trading in its securities happening on a basis that is not reasonably informed. Typically, this will arise where a listed entity has become aware of information that a reasonable person would expect to have a material effect on the price or value of its securities but it is not in a position to make an announcement about the information to the market promptly and without delay." i.e. they know something but need time to figure out exactly what to the extent that they can fully inform the market.