I am curious to know if there is time decay associated with Ultra (bull) ETFs. I understand the tracking error associated with these ultra ETFs due to volatility: if the underlying index declines 10% in a day, then for a 2x Ultra ETF it would decline by 20%, so it would only take a 11% gain for the underlying index to break even but it will take a 25% gain for the 2x Ultra ETF to break even. However, I don't consider this as "time decay". I looked at the daily holdings of Proshares Ultra ETFs and it seems they use swaps to achieve the leverage. Is there "time decay" associated with SWAPs as is the case with options? I also looked into their fund prospectus and time decay is not mentioned as one of the risks.