Using the power kernels of Phillips, Sun, and Jin (2006, 2007), we examine the large sample asymptotic properties of the <italic>t</italic>-test for different choices of power parameter (<italic>ρ</italic>). We show that the nonstandard fixed-<italic>ρ</italic> limit distributions of the <italic>t</italic>-statistic provide more accurate approximations to the...

Financial practices often need to estimate an integrated volatility matrix of a large number of assets using noisy high-frequency data. Many existing estimators of a volatility matrix of small dimensions become inconsistent when the size of the matrix is close to or larger than the sample size....