More and more grocery retailers are becoming multi-channel retailers, as they are opening an online alternative next to their traditional offline supermarkets. While the number of multi-channel grocery shoppers is also expanding at a fast growth rate, there are still large differences in online shopping frequency, and as a result, in the levels of experience with buying in the online grocery channel. This study wants to (i) identify the underlying drivers of online store choice and (ii) explore if and how these drivers change when multi-channel shoppers gain online grocery shopping experience. We investigate this question with an online store choice model using purchase data of an extensive UK household panel over a two-year period, covering all multi-channel retailers in the grocery market. Our results show that multi-channel shoppers, at the start of online grocery shopping, tend to select the online store belonging to the same chain as their preferred offline store, especially when the online store is strongly integrated with the offline store in terms of assortment. When online grocery shopping experience increases, multi-channel shoppers' focus shifts from a comparison within a chain across channels to a comparison across chains within the online channel, resulting in an increasing importance of online assortment attractiveness and online loyalty when choosing an online store.

A switch from single-to multichannel grocery shopping can affect consumers' purchase allocations. This study investigates whether and to what extent a consumer's decision to start buying groceries online at a particular chain can lead to expansion of the share in grocery spending allocated to that chain. To obtain a better insight into the underlying mechanisms and to provide more accurate and refined managerial guidelines, we further investigate the moderating effects of a comprehensive set of factors that may stimulate or withhold these expansion effects. To analyze these effects, we use a large and representative U.K. household panel data set, composed of multichannel grocery shoppers and a matched group of single-channel shoppers, for a 2.5-year period across all multichannel grocery chains. The empirical analysis confirms that multichannel grocery shoppers expand the share of wallet allocated to the online-visited chain, and that the extent of this expansion depends on chain as well as consumer characteristics. Expansion effects appear to be more profound for chains that adopt an integrated multichannel strategy for product prices and category assortments. In addition, customers who face more stringent time constraints, live farther away from the chain's offline store, and/or purchase fewer competitive private-label or hard discounter products, are more likely to increase their share of grocery spending at the online-visited chain.

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