Depends when and how they covered. If they all covered, it would likely be for certain reasons, and so there would be a lack of sellers. But to humor you, well, maybe 10 cents per 1 million shares? Kevin Douglas bought 8.5 million shares from Sep 10 to Sep 14 and sent the share price up about $0.65. So if 25 million shorts all covered over a span of a couple of weeks it might send the price up $1.50 to $2.00. Maybe someone else has a more scientific answer for you.
If you look at short interest, it doubled between April 30 and May 15. The TMEDS were announced on May 7th, and then May 7th and May 8th were the two highest volume days so far in 2012, generating 13.55M and 17.27M on the two days. These blow all the other days in the year out of the water. This was a coordinated attack because whoever shorted it knew exactly what they were doing and what the TMEDS meant. So in these two days the stock crashed from $5.53 to $4.21, and would then go to around $3.50 the week after.
So since the majority of shorts are probably in TC around the $4.21 to $5.53 mark, we can expect this range to move quickly once TC begins moving towards that area, although, I get the feeling a lot of shorts are owned by the same person and/or institution. But still, I honestly think Kevin Douglas buying 8.5 millions shares really threw the shorting person(s) for a loop. Take a look at the short interest chart, and you will see that they had basically stopped shorting this. For 3 periods in a row, short interest stayed at 21 million. Then Kevin Douglas bought from Sep 11-15, and suddenly from Sep 15 to Oct 31, short interest jumps to almost 26 million.
I don't think the shorts were planning on having to knock the stock back down from a spike like that and blew another 5 million shorts. Now they are either really smart, or they are screwed and can't figure out how to get out of this mess. It would take a lot of shorting to get TC back anywhere close to $2.50 or under. I think their goal all along has been to keep this under $3, or as close to $3 as possible to avoid any institutions stepping in. But they can only keep it down so long. The thing is, share price is really irrelevant without volume. Even the most recent run down to $2.52 was done on weak volume, way less than average. I just don't see this stock pushing any lower. It's out of gas. The shorts may be able to keep the price suppressed for a little while long (below $4) but eventually it will break out. People are just going to stop selling eventually.
Thank you both for your answers, very interesting. I have 2000 shares that will be put to me at $6 a share, December. My break even will be $5.25. I want to do something soon to bring down my break even cost. I still think TC will go a bit lower and break out of the triangle it's in on the low side, buy some shares, then have it go up. I could also sell 20 calls to get my shares called away after I get them.