Do not intiate long term trades using these inverse etfs. They are only a play on short term volatility and that's it. Check out EEM chart and EEV. EEM is the MSCI Merging markets Ishares and it's Inverse ETF is EEV. Look at the two charts.
Clearly, just like the rest of the market EEM took a pounding and was is down over 50% over the past year. Now, look at EEV, it should be UP a lot, right? WRONG. It is actually down over the past year. Yes, there were periods where EEV scored some super nice short term traders but if you went LONG the EEV after correctly concluding that EEM would take a beating, you were right on EEM but dead wrong by using the EEV ETF to capitalize on this analysis.
Conclusion: These inverse ETFs are for very short term directional moves ONLY.
WARNING: Once you realize that you are caught on the wrong side of these inverse ETF trades: GET OUT asap and ask questions later because once they move, they MOVE FAST and they MOVE BIG. Scratch the trade and protect your capital.