I have an alert received for Citibank (C) June 4 calls - high volume. There were more than 125,000 contracts traded today:
At $0.21, they give roughly 20X leveraged if the stock moves over $4 by June. The issue with buying options of penny stocks like C is that you are better off owning the stock outright as there is no time decay. In this case, however, the leverage is still reasonable. The move required is about 15%, which is not bad also.
The high volume appears to have been triggered by one rather large trade:Technical Trend Analysis Tool, (powered by INO).