Expected idiosyncratic volatility and its positive relation to expected returns of Fu (2009) can be closely replicated, but only when we include information up to time t to estimate the idiosyncratic volatility at time t. Since this involves look-ahead bias, we re-estimate expected idiosyncratic...

We study options market participants’ trading behavior before and after the options multiplier increases. After the options multiplier increases, the options market becomes more efficient. By analyzing the high-frequency microstructure dataset, we show that local retail and local institutional...