scarlet, I noticed you never received a response to your question but this has been an issue that has been discussed many times over the past year that I have been involved with GTE.
It is a requirement of the SEC to notify shareholders when a company official intends to sell stock. Notice the date of the transaction, February 15. What you aren't told in this notification is that there is no certainty that the person actually sold the stock nor does it tell you how many shares the stockholder still has in the portfolio.
This could be a planned sale to handle personal business, to meet company requirements such as an option time limit, or it could be an attempt to test the market. I would be very concerned if this COO sold all his holdings but that isn't the case.