Big investors usually does not trade in AH . Because they won't get as many shares as they want.
Look at the chart . When the company announce a good news in 10-29-2004 , they stock jumped +$3.36 and closed at the high price $60.36.
I think now , the stock will close at least > $59 .
keep in mind , the company announced a $110M stock repurchase . This represent almost 2M shares at these prices which is equal to 12% of the Float . This is also good . Overall,investors are really comfertable with the company and this is why the company got upgraded some days ago .