S&P 100 Index Option Volatility
利用标普100指数期权交易数据，研究常见估值简化对隐含波动率时间序列性质的影响，发现非同步观测和买卖价差会引入虚假的负序列相关和负交叉相关。
ABSTRACT Using transaction data on the S&P 100 index options, we study the effect of valuation simplifications that are commonplace in previous research on the timeseries properties of implied market volatility. Using an American‐style algorithm that accounts for the discrete nature of the dividends on the S&P 100 index, we find that spurious negative serial correlation in implied volatility changes is induced by nonsimultaneously observing the option price and the index level. Negative serial correlation is also induced by a bid/ask price effect if a single option is used to estimate implied volatility. In addition, we find that these same effects induce spurious (and unreasonable) negative cross‐correlations between the changes in call and put implied volatility.