$2.50/share margin account balance requirement. Essentially "insurance deposit" to protect the broker against price rise.
"...Well. Thanks for clearing that up. Everyone on here is saying there is 2.50 per share charge when shorting a penny stock, that isn't the case. ..."
"It is easier to fool someone, than to convince them they have been fooled."
For those that don't get it, it means that people need to be more careful, and do good due diligence.