There have been some really good DD's here and other subreddits re: GRPN, you can easily search for those and read up on them. I've been watching for a few days now and was waiting for a big sell-off (which seemingly always happens before a big run-up).
It's running \~70% short right now and the short interest is trending down while the % short of float is going up. Shares are being returned but the float is dropping. There is very large institutional ownership as well. You can read through the really excellent DDs out there, but I like to watch the price action.
It dropped \~10% yesterday but on relatively low short volume. I entered yesterday afternoon as it rebounded, it is trading incredibly thin today, big movement on a little volume - it's up \~5% today on 15% of yesterdays volume. Put this one on your watch list.
Positions:
75 Jul17 25C (will be closing this today/tomorrow at the absolute latest)
200 Aug 30C
here is one of the really excellent DDs:
[https://www.reddit.com/r/Shortsqueeze/comments/1ui26kj/grpn\_update\_1268m\_short\_1638m\_on\_loan\_new\_borrows/](https://www.reddit.com/r/Shortsqueeze/comments/1ui26kj/grpn_update_1268m_short_1638m_on_loan_new_borrows/)
This trend in short interest and decline free float is something I haven't seen in several years.