It is related to second-guessing, which has been discussed here:
double guessing - WordReference Forums
In fact, I suspect that different people use these words in different ways. Usually we can get a feeling for what they are trying to say by the context of their sentence. It is a matter of nuance.
Good & informative tips.The term penny stock refers to any stock that is traded outside one of the major exchanges. The definition of a penny stock is a low priced speculative security.