Computing average return on negative returns (gemoetric mean)

Question

So let's say a portfolio created a loss (leveraged portfolio) of $104\%$ in six months. What would be the average return be per month?

My guess would be $(1 + 1.04)^{\frac{1}{6}} = 1.126$, so my portfolio would create a return of $-12.6\%$ a month.

Is this correct or am I overlooking something?

Thanks