buy-back, page-5

You'll find that some companies have a policy of stopping a buy-back if they are working/are aware of potentially price sensitive information. If they were to buy, there is a perception (right or wrong) that they are insider trading on their own information.

However, this isnt to say that their is positive information. Just that they are working on something or aware of something. For eg, last weeks annt of the contract came.

There maybe more.