🤖 AI Summary
This study addresses the downward bias and inefficiency of conventional realized variance estimators under discrete observations by proposing a novel high-low range–based estimator for the quadratic variation of continuous semimartingales. The method replaces squared returns with normalized squared price ranges, yielding a consistent and asymptotically mixed normal estimator that effectively corrects bias induced by non-trading periods. Leveraging probabilistic limit theory, continuous semimartingale modeling, and high-low price statistics, the approach achieves an 80% reduction in theoretical variance compared to traditional estimators. Empirical analysis using TAQ data demonstrates that the proposed estimator substantially outperforms existing benchmarks in terms of estimation accuracy, efficiency, and robustness.