They must have, otherwise the product could not be financed.Quote from crgarcia:
Leveraged ETFs have no time decay.
The issuer of such an instrument can use options or futures/stock to manage it. The expected value of the financing costs when using futures/stock is equal to the cost of time decay of the options necessary to have the same effect.
So a long/short ETF has a lower/higher value over time than you would expect from the multiplier.