The earliest study by Tinic and West (1974) showed lower bid–ask spreads for 112 Canadian stocks cross-listed
on US exchanges than their purely domestic peers. Of course, the data were low-frequency and limited to one market (Canada–United States) and for a relatively short period of time. The increased availability of transactions level data for other markets spawned many follow-up studies. Forster and George (1995), Chan et al. (1996), and Werner and Kleidon (1996) examined intraday patterns in bid–ask spreads, price volatility, and trading volumes in mostly developed-market ADRs after they have cross-listed on US markets. Werner and Kleidon, in particular, uncovered unusually high volatility and trading volumes at the open for Japanese ADRs (following Tokyo’s close) and around 11.00 a.m.