If you are a Long Term holder of a stock, you are considered a strong holder (one who will hold through Good times & Bad) and the Pro's are of little worry to you.
If you are a trader or an investor with shorter time frames, you need to work in harmony with the pro's, not against them. This way, you buy when you can see them buying & sell when you can see them selling (you let them make the decisions on at what price and time frame, it would appear that for Exco they have been using a range of around 20%), and they will not pose any problems for you.
It is only the Weak holders (often day & momentum traders in particular) who are in the most danger of getting caught on the wrong side of the market, and the pro's will keep them there for as long as possible, in an effort to make them sweat to take a loss and sell their shares back into the market to get out.
Here is a chart that shows how the Pro's use the company announcements to their advantage, you can also see where they are buying at the lower prices (check the volume), also notice how the volume falls right away before a rise in price showing there is no supply, so the SP can rise easily with little absorbtion volume (pro's buying to push the SP) sorry it got a little busy.
cheers
EXS Price at posting:
60.0¢ Sentiment: Hold Disclosure: Held