I posted a few weeks back about this...yes, the 1x inverse ETFs will decay, just not as badly as the 2x ETFs. I would suggest plunking some numbers into Excel to simulate volatility and compare to 2x (e.g. how much does something decay if it moves +3.00% -2.50% + 2.80% vs. 1.50% -1.25% + 1.40% over a few days).