I have to dissagree, a back out by Teck will result in a serious decline in the share price so thats why they were shorting the stock in january.

Since they have rapidly covered, they have to have a reason why they have changed their tune.

Shorters cover imo because is its too big of a risk too short this stock.

When there is a back-in or offer this cause a halt, and the shorters won't be able to recover their positions. The difference between the buy-out price and the shorting price will be their loss. There are to maximal pnl scenario's.

Their max profit

Their profit is maximised to 0.77 (with the Banckruptcy of CUU which is ofcourse less likely). So you do the maths.

Their max risk

We all know how much that can be. 3.00-0.77=2.23 ps loss. Good luck with defending that to your trading team leader, ouch!