I'm not a shorter, so not sure of their thinking, but would shorters take the risk of shorting BBG, knowing that BBG can go into a trading halt any day now when TPG finishes their due diligence?
Bain Capital pulling out, as mentioned could be taken as a sign that they know due diligence is finishing soon, and know they can't compete with TPG's offer. (this is all speculation of course but you never know)
BBG Price at posting:
$1.11 Sentiment: Buy Disclosure: Held