“…Earlier studies that compare the forecasting power of option‐IV and GARCH‐type models generally conclude that the former outperforms the latter (e.g., Day & Lewis, 1992 in stock markets and Jorion, 1995 in foreign exchange markets). Instead of daily data used in GARCH‐type models, recent studies increasingly use models based on intraday data and realized volatility (e.g., ARMA or ARFIMA) and find that such models generate comparable or even better forecasts than IV (e.g., Kambouroudis, McMillan, & Tsakou, 2016; Martens & Zein, 2004; Pong, Shackleton, Taylor, & Xu, 2004). However, IV still provides some incremental information and thus improves the forecasting performance when it is combined with model‐based forecasts (Busch, Christensen, & Nielsen, 2011; Haugom, Langeland, Molnár, & Westgaard, 2014).…”