Yes, and eventually they must cover at SOME point -- unless, of course, the issue being shorted actually has the possibility of going belly-up (which I am sure is not the case with ACI.) The question is, naturally, at what POINT do they cover? That's the million dollar question.
you are wrong. its even worse than you suggest right know. the majority shorting aci are getting in and out of their short sale by covering and cashing out then reestablishing another short sale driving the price lower and lower. There appears to be no favorable news of any consequence to stop this cycle anytime in the foreseable future. ACI's 4th qtr earnings release was a killer, the best they could offer is that maybe the 2nd half of 2013 things will slighlty improve...pretty weak guideance.