“…In particular, the estimated HIS's depend on the ordering of the price series—the HIS of a market is the largest when it is ordered as the first market and smallest when it is the last. Consequentially, the HIS of each market is identified only up to an interval, and one needs to compute the midpoint between the minimum and maximum values obtained from all possible permutations of orderings to derive the point estimate (Baillie et al, 2002; Hasbrouck, 2003; Lien & Wang, 2019; Ozturk et al, 2017). As a remedial approach, Hasbrouck (2019) proposes a method to lower the contemporaneous correlations of the price series using high‐frequency data, so that the gap of the minimum and the maximum values could be reduced.…”