I've seen many BKs holding ridiculously high valuation almost to the day the stock is cancelled, even when all hope for a buyout is gone. It's a puzzling phenomenon and it has been the subject of some articles over the years. No doubt short-covering plays SOME role in supporting the shares.
I'm a general believer in the Efficient Market theory, but in late-stage BKs, it breaks down. (there are several other situations where it breaks down too).