“…Another group of studies applies existing weak‐form EMH tests in rolling estimation windows 14 . Examples are the rolling VR tests (Tabak, 2003; Kim and Shamsuddin, 2008; Hung, 2009), rolling ADF unit root test (Phengpis, 2006), rolling bicorrelation test (Lim, 2007; Todea and Zoicas‐Ienciu, 2008), rolling parameters of ARCH models (Degiannakis et al , 2008; Alagidede and Panagiotidis, 2009a) and rolling Hurst exponent (Costa and Vasconcelos, 2003; Cajueiro and Tabak, 2004b, 2005d, 2006, 2008; Zunino et al , 2007). The application of a rolling window essentially captures the persistence of stock price departures from a random walk benchmark over time.…”