Function returns Realized skewness, defined in Amaya et al. (2011).
Assume there is \(N\) equispaced returns in period \(t\). Let \(r_{t,i}\) be a return (with \(i=1, \ldots,N\)) in period \(t\).
Then, the rSkew is given by
$$
\mbox{rSkew}_{t}= \frac{\sqrt{N} \sum_{i=1}^{N}(r_{t,i})^3}{RV_{t}^{3/2}}
$$
in which
\(RV_{t}:\) realized variance