Here is a chart from Fronteer that were bought out early last year. Notice the spot where the sp declined considerably just before the offer. The same thing you see in Arequipa,s chart. And here is a link to Daylight energy chart as well, where you see a similar pattern.I should also note that there are other buyout charts from different companies that are flat or have a steady increase before the offer.
http://ca.advfn.com/p.php?pid=qkchart&symbol=A%5EFRGhttp://ca.advfn.com/p.php?pid=qkchart&symbol=T%5EDAY