Abstract: With the rapid development of e-commerce and information technology, more and more manufacturers sell products directly to consumers through online channels as well as through traditional channels. However, competition between channels could be caused by the introduction of manufacturers’ online channels, especially when a manufacturer sells the same product in both channels. When the same product is sold in different channels, there will be product substitution issue, and when one channel is out of stock, the substitution is more significant. In other words, when one of the channels is out of stock, some consumers of that channel will switch to another channel to buy products. Meanwhile, in recent years, the global warming caused by the greenhouse effect has received increasing attention from the government, the public and scholars. Governments all over the world have formulated and implemented relevant low-carbon policies to curb emissions, among which carbon tax policies are one of the effective mechanisms. As more and more countries and regions have been implemented carbon tax policies, companies have to consider the impact of carbon tax policies when making operational decisions. Due to the differences in carbon emissions in the dual-channel supply chain, companies in the dual-channel supply chain need to consider the impact of carbon taxes. Based on those, a dual-channel supply chain model consisting of a single manufacturer and a single retailer is established under a carbon tax policy. On the basis of considering the stock-out conversion between channels, the issue of dual-channel inventory competition between channels under wholesale price contracts and two-way revenue sharing contracts is studied, and a combined contract mechanism consisting of two-way revenue sharing contracts is designed and payment mechanisms are transfered to achieve a win-win situation for manufacturers and retailers and ensure the effective execution of the contract. It is found that under the wholesale price contract and the two-way revenue sharing contract, as the carbon emission difference between the traditional retail channel and the online channel increases, the manufacturer should adjust the wholesale price and the ratio of revenue sharing to control the inventory levels at the dual channels. The optimal base-stock level at the online channel increases in the unit-product carbon emissions at the retail channel. The optimal base-stock level decreases in its own unit carbon emissions. Further analysis shows that the effect of the differences in carbon emissions between dual channels on the optimal wholesale price and the optimal base-stock levels at both channels also depends on out-of-stock conversion rate and carbon tax rate.

Key words: dual channel supply chain, inventory decision, carbon tax policy, supply chain coordination