The ProShares Ultra VIX Short-Term Futures ETF is not a good long-term investment, despite its potential for dramatic short-term gains during market stress, due to its return of -83% since inception.

The VIX index is known to be mean-reverting. Its level is expected to trend toward its long-term average over time. The VIX is currently rather low, so one could bet on a rise in the VIX with UVXY.