Abstract: With the development of omnichannel retailing, a growing number of e-tailers start entering the offline marketspace in order to expand the market demand and profit. The condition under which an e-tailer should adopt omnichannel decision is studied and multiple influence factors are considered, including different consumer-oriented types, consumer patience and unit operation costs in different channels. The multinomial logit (MNL) framework is adopted to characterize the consumer choice behavior in the basic model which the e-tailer only operates the online channel, and the optimal assortment and price are obtained. When the e-tailer adopts omnichannel decision, if the consumers are product-oriented, the MNL model is also adopted characterize their choice behavior; if the consumers are channel-oriented, the nested multinomial logit (NMNL) model is adopted to characterize their choice behavior. First, optimal prices for arbitrarily online and offline assortments are obtained. Then by analyzing the optimal price expressions, optimal assortments offered in different channels are obtained. Finally, by comparing the optimal profit with the basic model, the e-tailer's entry conditions under different consumer-oriented types are obtained. The results show that the products offered in the same channel always have the same optimal price, means that the e-tailer only needs to decide two prices: the online price and the offline price. The optimal delivery time is only related to the delivery cost function expression and the consumer patience factor. If the consumers are product-oriented, only when the difference between the dual channel operation cost is relatively small and the consumer patience factor is relatively large, the e-tailer should adopt omnichannel decision. The optimal assortment is offering the most popular product offline, and offering the remaining products online. If consumers are channel-oriented, omnichannel decision is always profitable for the e-tailer. The optimal assortment is offering the most popular product offline, and offering all products online. The results of this paper can provide some references for the e-tailer's channel, assortment and price decisions.

Key words: assortment, omnichannel decision, consumer-oriented types, price-delivery time joint decision, delivery cost