BBUS, page-12963

More like a compounding decay, simply:

You buy BBUS today $1.345 - index goes up 10% overnight, you lose 10% = $1.21
Next day index goes down 10% - BBUS gains 10% = $1.33 = 1.5c decay.

So it resets every day. Every time the index goes up a certain %, you need a sharper move to the downside to profit.

Consecutive green days for the underlying index hurt the LT investment. Days of high volatility up down up down can also chew away the benefit.

You have to try and time a prolonged downturn. If you do and there is a big market correction, you'd be doing better than most, but tricky in this market.