thanks clak!  fascinating- that definitely answers the question.  so it's for sure shortable... currently 35,000 shares.

i wonder how people trading pennies with IB justify the comms.  i've used them off and on over time, but when i started dabbling with pennies i looked at the comms and couldnt figure out how anyone could justify it compared to a $7-10 per trade structure. 

for example, in their flat rate structure, buy 100,000 shares at 0.005/share, $500 commission (does not exceed .5% of notional).  in the cost plus structure, suppose you're not terribly active but your volume is somewhere in the middle of their tiers because you're trading pennies.  say you're at the 0.002 tier ... it's still a $200 commission, unless i'm missing something.