Question: When is it wrong to buy too many shares?
Answer: When you have just announced your intention to bid for a listed company.
This is what appears to have happened in a mix-up with the BT purchase of Plusnet that started on 16th November 2006. Reuters.co.uk is reporting that 17.1% of PlusNet plc shares were bought on the day of the announcement, but during the following day BT increased its share to 32.4%, taking it over the 30-percent threshold which would require it to make or amend an offer for the remainder of the share capital. BT's legal advisers discovered they owned too much of PlusNet too soon on November 21st and then started to sell enough shares to take it below the 30% threshold.