Online shopping is growing rapidly in many sectors, particularly in the retail grocery sector. The rise of online shopping poses some questions for retailers and manufacturers. First, to what extent does the online mode attract other retailer’s customers, as opposed to one’s own current in-store shoppers? Second, is online shopping resulting in more retailer cross-purchasing by consumers? Next, does brand loyalty differ across in-store and online? Lastly, how do private labels perform online compared to in-store? Using data from multiple categories in the UK, this study finds that (1) online sales for a retailer come disproportionately from its own in-store customer base; (2) there is an ‘online-buying’ market partition across retailers; (3) online-induced retailer cross-purchasing is increasing over time; (4) brand loyalty is somewhat higher for online purchasing; and finally (5) private-label brands enjoy slightly higher market share online than in-store.